You don't want to go running into firefights guns blazing. Stay back with a pistol or other somewhat ranged weapon and take on the enemy from afar. [u]Only[/u] attack close up you can either a.) get the drop on them from behind with a melee b.) can use cover to move in on the enemy and use a closer range weapon or c.) if you are with teammates and can have them distract the enemy while you move in for the kill. Don't go running straight through the middle of the map in BTB or big slayer maps and if you ever decide to play Breakout remember: you don't have shields so you can't go running to an enemy and expect to not get killed by a pistol, DMR or BR headshot because those things can two shot you (three shot for DMR and pistol). Oh and don't be afraid to use the noob combo on enemies. (Plasma pistol and a pistol or other precision weapon.) Edit 1: Only go for the power weapons if you know that you can get them without dying. I've made that mistake far too many times.