My tactics

When I spawn I look for a weapon nothing sucks more that to be attacked when
you have nothing.Then I try to collect other essentials medkit,cookies,
and armor. Anything I might need to kill and stay alive. Dual uzis work
well as long as you have lots of ammo and uzis use that quickly.
Riot guns are veryeffective firing a wideband shot and dealing a healthy
amount of damage. The rail gun is also very effectivealthough slow
firing it deals a great amount of damage. Generally one to two shots will
kill your opponentThe rocket launcher is one of my favorite weapons because
you can then use heat seekers. Even the standard rocket deals a great amount
of damage and aiming at the ground can deal damage to a moving opponent
(provided you don't aim at your feet. You aim at their's).

The grenade launcher is effective for going around corners I wouldn't
recommend using it I n close confined areas where the grenade will more
likely hit you. Sticky bombs just make good traps in a firefight I wouldn't
recommend them though. The guardian heads flame thrower and ring of fire
are some of my favorite things to use and the rings deal lots of damage to any
one who runs jumps or falls into them. In fights I cannot stress how important it is to keep moving you stop you die. Jumping and strafing are good ways to avoid being shot in a duel or large battle.
You also should use jump and strafe when collecting items to make sure anyone behind you has a harder time hitting you. If you run out of everything in a battle and all you have is shurikens unless you KNOW your opponent is severely injured it is time to run.
If you happen to see a large fight taking place from a distance feel free to fire a few rounds into the fray. You might get a kill. If you can try to block weapons or crucial items with sticky bombs. I don't
mean camp camping is stupid and takes a lot of fun out of the game. If you are looking for somebody to kill check
areas with good items (fortune cookies, portable medkits, rocket launchers).
Also have varying routes to items as well as escape plans if you rotate your
routes players Wont be able to pick up on them easily. Knowing the map is
very helpful for this to be effective. If you have BUILD you can check out
the map in there or just test play the map yourself to find out where
everything is and look for hidden goodies. Make sure that you also find
the level intersting and fun to play. Ugly and really stupid maps are
boring and kill any fun you could be having. Also keep a setup that allows
you to acess everything you need quickly(default controls is not a good key
setup).
Good luck and happy gaming :)