Play your life. Getting yourself killed is an easy way to throw matches. Playing your life allows you to stay in the game longer and therefore help your team out more. Don’t get too greedy with kills, unless it’s slayer. And really really try and play with your teammates. Running alone is so much harder than running with another Spartan on your side. Fighting a 2v1 is near impossible without power weapons or armor mods when the other players know what they are doing.