Hard to offer solid tactics, so I'll offer a few common scenarios and their basic principals.
Patience is definitely key to successful sneaky bastardry, and this is the best way to shoot more people than you get shot (perhaps often not best to win objectives/points, might have to leave your team to do that while you increase their chances with lots of kills). Also not wasting valuable time to revel in shooting people/ capturing an area when you could be making a decent advantage and many more kills from it.
During a game people will develop an idea of what areas are controlled by them and what by the other team. The further away from the front lines you go, the more complacent people get, and a couple corridors/rooms away they'll all just be casually strolling up the the front lines guns pointing at the floor, unless they're new to the site and don't know where they are lol. It's better to keep sneaking further behind the lines and clear a whole room of people than move parallel and only get a couple. So after you get past the front line you're free to rush around more, as your unlikely to encounter someone waiting for you/camping a doorway etc, just unprepared strollers.
In this manner if you can defeat/sneak-past/let-go-past-you an initial group to get past the front-line, you can then shoot lots of people guns down strolling up to it while you dash through to another section of the front-line and shoot them all in the back because no-one's covering the door/direction their team is coming from.
To achieve you might have to let people pass you while hidden in a corner etc. But again patience is key, if you hear someone coming, why pop out and engage them (and probably get them due to surprise) when you can let them and their team-mates pass and shoot all 3 in the back. Then if you can dash through to where they came from before they start walking back, their team won't have seen it happen so wont be expecting enemy coming through where they just saw their team push into. It's all a judgement call based on whether you have space/time/opportunity.
Gun ho tactics are best used when there's a corridor stalemate or similar. You'll probably get shot more than you shoot in these situations, but the sooner this stalemate is resolved by one team pushing more than the other, the sooner you can get back to being a sneaky bastard.
One point I'll make is about the 'casual strollers' is this is in my experience when people cheat the most in airsoft. If someones strolling up to the front line in a zone they consider their teams/safe and they feel a hit, their first assumption isn't going to be 'oh my god the other teams pushed forward this far', it'll be 'oh god some muppet on my team who doesn't know where they are has shot me, i'll ignore it'. I've found it's 50/50 at best to whether they'll take the hit without you having to point yourself out to them. I've lost count of the number of times the opp has responded with 'wtf are you doing' or 'i'm on your team' and me have to say 'i'm shooting you, i'm on the green team' or 'no we're not, I'm green and you're dead'. A best-case scenario is someone taking the hit but not realizing it was you or you're on the opp team and storming back to respawn muttering about team-killers, as that wont spoke the rest of them. To me it seems like the CQB equivalent of the common woe of snipers in woodland skirmish.
I have the luxury of a site where there's many available routes and much potential for flanking, I'm not sure what it's like at strike-force but might be a bit linear/square from the looks of it, and much harder to get past the 'front'line'.
So yeah, basically try be patient and maximize the potential for shooting lots of people in a sneaky/cowardly fashion, rather than spend your advantage on shooting one/two in a fair fight.
As you can imagine I am much loved for such tactics at my local CQB site, and the average airsofter is mature enough to not get emotionally frustrated about being shot in the back a dozen dif times, certainly not to the point where they'll bitch or even make false claims of having hit you when they do finally get a 1vs1 fair opportunity (which you gotta agree to as why not give the guy something to keep their ego balanced, unless they're well rude, then they can go f*ck themselves and waste a marshals time following me around for a game if they really feel the need)
