I have a laser/flashlight combo thingy on my gun, don't really use the laser but the flashlight I use all the time, came in really handy in the CQB game last week, just give it a quick flash as you go around a corner to try and catch an enemy guy off guard, also we'd try and team up in pairs, and have one guy crouching down with the other standing above him to give extra fire through a doorway.
In my case anyway, when I first started playing airsoft there wasn't much in the way of tactics really being done while playing but now that we're kinda building a team together we find ourselves doing tactics more and more during games, like stacking up going into a room or even just trying to coordinate and assault, we use basic hand signals and have radios now too so its easier to commumicate and know what everybodys doing or where they are...
Played an intervarsity game last year, they had supposedly trained a lot but did very little actual skirmishing, we had kinda gotten an idea skirmishing against ourselves of what each person is like an picked out our best 10. Not to be bad but we won 3 out of 4 in the intervarsity and i like to think it was better tactics that won it for us, good tactics win games, fact!