I noticed you don't defend rifleman. If I see your team is full of people who never defend, you can bet I'm sneaking in to c4 your base in a hurry and just hope I don't run into one of you along the way.
In sudden death, it only takes 4 c4s to take out the barracks and research centre. Why wait for a nuke/ion strike? Place a nuke strike and 4 c4s at the same time, the nuke wont even reach 15 seconds countdown before the 4 c4s did the same job faster, quiteter and for a whole lot less money.
Out of sudden death, it takes 4 c4s to take out the obelisk, 6 for the repair facility, 8 for research center and barracks and 12 for the refinery and war factory. That's one refill for barracks and research centre and two for refinery and war factory. There is no point in hanging around to try to put more than that but be cautious because some maps have odd "Impassable" lines for the c4s infront of the terminals which means it will take more than usual to bring a building down. Usually frustrating for a utility c4 strategy guy like me. Use it to your advantage for defending too; if you see 6 c4s on your repair facility, know that it will be destroyed unless you do something about it! The same goes for any building if you know just how many it takes to bring down and when.
You said it best rifleman, rocketjummping gives you an edge. Some maps you almost have to rocketjump or you're trapped. Some classes can rj easier than others, and fireproof is one hell of a boost to taking less damage rjing, something to keep in mind. With some weapons, if you can time it perfectly you will not take any fire damage at all, so practice is key to surviving with low hp in a tight spot.
Timecop is one of the best classes to take out the obelisk with. It's almost always well guarded with mines and fake crates, so boost in there with 4c4s, because the enemy expects no one will be able to get in, so they wont check for c4s.
As for utility guys. It's a real shame to see utility classes being played badly because it's by far my favourite class. When sandbagging doorways, think about which ways the enemy can enter the easiest. Block them off and leave the doorway most needed by your allies open. Use fake crates sparingly, there's only 15 of them, they're easily destroyed and if an ally is close to one when they go off, they'll die. Place them where they're hard to see and in strategic points where your allies are less likely to be.
You can lay 54 mines as a utility guy. Simply make 50 and using your repair gun, you can detonate 1 mine and lay another 4. This is important, because if you cover every doorway with mines, and double mine the obelisk, you'll find you're one door short. This trick lets you cover them all! And as mines go, watch obituaries! Someone tripped a mine? One of your doorways is now undefended. Find it and replace those mines because they'll be coming back to the same spot thinking they've just cleared it, if they haven't told their team that doorway is clear already. If you're playing utility, maintain your base. Get sloppy and you're letting the enemy in without a fight. The disarming trick isn't well known, judging by how many cry about how the mines they were repairing over mysteriously went off. Use this to your advantage. If one of your buildings was destroyed, then repair your own mines to destroy them because it's not somewhere you need to focus on anymore and you can always use more mines for somewhere else.
One tip is to lay mines or fake crates over the healthpacks inside your base, because when an enemy is inside it and they're under fire, where is the first place they go? To the health packs! I wish mines and fake crates gave exp for that because I can't tell you how many got killed because of that XD
Put up a powerup cache ASAP. It's critical in the early stages of the game for your team to have the upper hand. It's disappointing to join a game to see no powerup cache in the spawn area. Often I'll make one myself as soon as I can if there is none.
Utility as a bare class, without getting any extra weapons isn't the greatest for combat, but both of your weapons you can spawn yourself allow you to shoot from a distance. Use that to your advantage. You lack speed compared to most classes so if you venture into the field, never ever leave without spawning yourself a weapon, make sure you have cover and snipe your way forwards slowly. It goes without saying, but spawn yourself a weapon as soon as you can, even when you're just putting up defences in your base. It's where the enemy wants to go, so make sure you're able to defend yourself or you'll find yourself losing $650 to buy utility again pretty soon.
One thing I see a lot of is utility players assumming sandbags are the be all and end all. They aren't. You can rocketjump over them with ease and can actually help enemies take cover and hide. Place them wisely and maintain them. They're not great defence, and as you can't shoot over them well, they're not great cover. Make sure they're assisting your team, not hindering them.
Use the layouts of all maps to your advantage. If it's possible to stake out the powerup crate area, then do it. Make it easier to get there from your side of the map, anything just to make sure your team has the upper hand. If there are small tunnels, mine them, fake crate them, put turrets up, anything you can to stop the other team getting through, and maintain it. If there are wide open spaces, use lrm turrets to halt the enemy. It's often the case I see great ideas for defence in the middle of the maps, only to see them disappear within a few minutes. Evey time a team wins due to a utility guy, it's because they kept maintaining those defences.
If you're set on playing utility guy, then play utility guy. More often than not someone will play utility for 10 minutes and get bored and leave the base unmaintained and everyone assumes the utility guy they saw before is still doing it. Tell people if you're not utility anymore. If you want to go out into the field, make sure you left the base well defended at every point. There is no sense in using half your resources to defend the base or strategic points just so you can go DM for 5 minutes and leave gaps in defence. As soon as someone's found a flaw in your defence, they're going to show others how to get in too.
The obelisk is your greatest ally as a utility guy, but never rely on it, ever. It's 4 c4s and that's it. What happens when the obelisk is gone? The entire enemy team rushes in all at once and if your defences are bare to none because you thought the obelisk would save you, you're done for. Plan ahead and place defences in place of the obelisk before it's actually gone. In some maps this can cost a game in one moment. The obelisk gives you a warning that an enemy is approaching, so scout out as stealthily as you can. If you can catch them off guard you can score yourself some easy exp. What you don't want is to get killed, so move carefully, and watch the obituaries like I said before; if someone commited suicide/tripped a mine, it means you have something to replace to greet them on their next visit.
Plan out your repairing carefully when you're under attack. What building is the most important and which one is under attack the most. Your repair gun is pretty weak, but you can keep a building from being destroyed until others come to help you. However, when repairing, keep in mind that others will try to use this break to sneak into the base. If there is already someone else repairing and they're keeping ontop of it, don't sit there and taunt whilst you repair with your inferior repairgun, go and make sure no one else is in the base and maintain your defences, because you can bet no one else is and whilst they're being destroyed under an attack, it's getting easier and easier for the enemy to sneak in.
There's been a trend to use ion/nuke strikes lately, and some wiseguys like to put them ontop of the research centre roof. Check it, and make sure you have a quick method to get up there just incase. During a nuke/ion strike, tell your team where it is! Half the time is taken looking for it, and being unsure of whether it's your teams or not. If you find it, take that 1 second to shout for help and tell them where it is briefly before repairing it. With ion/nuke strikes, the preferred method is to use stealth trooper to run into the base with it. They don't stop for anything! Your best defence is the mines. They have -10 armour on everything! Unless they have a lot of hp, they're going to die and they've just wasted a lot of money. During ion/nuke strike rushes, maintaining mines should be your top priority, because if one gets in, it was your fault. That being said, sometimes they will place them behind buildings. When it's not sudden death, and if they building has high hp, it's no concern, but alert the team. Whilst it's charging, double check the base is secure, because someone got in somehow and they might be around still to try to defend it. Make sure all doors are defended and turrets are placed strategically.
Speaking of turrets, if you're going to put them ontop of the research centre roof, learn the linedef layout of them; not all lines are passable and turrets can destroy themselves shooting these lines. Place them in places where they can actually shoot the enemy or you've wasted turret slots for nothing.
Sudden death can be a godsend or a nightmare. If you've kept ontop of defences the whole match and your base is at 100% then good for you, you really played your part well, but don't let your guard down. Now everyone has an ion/nuke strike and they want in. First check is turrets, you want to slow them down so your team can pick them off before they get in. Next is blockades; are the sandbags you put up in strategic places still standing? And lastly, double check those mines! Patrol the base to ensure every doorway is still defended. You don't want to lose 2 or 3 players whilst they're stuck disarming a strike because you didn't replace those mines.
I'm not sure if everyone knows this, but mines aren't instantly set off. If you go *near* them then run back, they blow up without hurting you at all. It makes them less effective than you might think, so don't assume that because you mined every door that the base is suddenly safe. I also see fake crates over mines a lot. That's really bad practice. If the crate is set off, the mines are gone too! Mines have health so be careful about where you put those fake crates. Something similar is kamikaze; it will take out all mines within a certain radius, so if someone set one off in your base, check those mines! They're not all going to be there anymore.
Something I see so little of, is having a runner do the dirty work of planting c4s for you whilst you supply refills for them. I know hardly anyone listens to team chat, but if you've spotted someone with strategic sense, offer to sit somewhere hidden to refill them from because chances are they're better armoured or a faster class than you. A similar strategy, is placing caches in the field. They're a lot more important than anyone is going to give you credit for, but be warned, the enemy can use them too. Lose that spot and it's suddenly a refueling area for the enemy.
If you lose the war factory, no one can use the refill screen anymore. Your time to shine! Put up some ammo and health caches in the spawn room. No one's going to thank you for it, but you can bet it's appreciated.
A really handy trick with these odd linedefs around the building's terminals is that you can stand ontop of them and look out into the base and repair by the splash damage from them. This way you can see if the enemy has just come in or an ally. You don't have to stop repairing every time you hear that door open now. One word of warning is that mines are somehow affected by it. If you point your repairgun at them whilst standing on a screen, it will set them off. Be careful.
Some maps require you to make stairs for allies that don't know how to rocketjump or play classes that simply can't. Glacier is a prime example. It's a lot faster to refine if you make stairs to the tiberium fields and it's a lot faster and safer to get the enemy base if you've made stairs over the crates in the central corridor. They seem like something to have fun with, but they can win matches if you use them to your advantage.
A word of warning about building stairs; when they explode they hurt you. Don't amass your base with stupid bridges of stairs leading nowhere, they block the fire of your allies and damage the base further. It might be fun but it's wasting time you could be spending on doing something useful. Also, don't make stairs that lead off the sides of the map and go towards the enemy base. No one is going to respect you for it. It's considered poor etiquette and again, you could have been doing something much more useful for your team instead.
If your barracks are gone, sit in the spawn room from time to time and spawn machine guns for people. They probably wont thank you but you know they'll be better off with them than the free classes. The same goes for losing your refinery. Not everyone has 12k to blow on good classes, so start making some machine guns here and there to help out the team.
All in all, utility is a class to assist your team, and believe me, they win matches. They can be used offensively to great effect too, but you're going to need to learn to move stealthily, and learn to navigate enemy defences well because you don't have speed and you don't have great armour or firpower. Get used to your speed and firepower, and learn how to sneak into bases and you'll be able to single handedly take down the entire base if you've got some luck on your side. Remember that you can fireproof yourself which not only nulls flamethrower but also protects against a lot of splash damage from various weapons. It's not to be overlooked lightly for just $100 for that little extra help.
The key to uility guy is to learn to be adaptive and read situations well. Lose a building? Help the team out with what they need in place of it. Lost the obelisk? Prepare defences in place of it to cover the areas it used to make more difficult to get to. Your team are camping a spot out? Go place some caches up to help them stay there to keep the enemy pinned down. Learn to be unpredictable in your defence style, because once the enemy sees you're building yours the way everyone else does, they're going to break in a lot easier. Try out some new tactics and show others some good utility practice. It's really not as boring as you might have thought if you learn to be creative and put yourself out there instead of moping in the base whining about how lame it is to make mines over and over, and it's always rewarding to see your team win thanks to your efforts (though, good luck getting thanks for it. If your frag count isn't up there I doubt anyone would notice you lol).
There's probably more but I'm most likely reaching some form of spam limit and about to break the tl;dr reply record lol That's it for utility tactics