Get a friend to provide supressive fire as you rush in quickly
They will be hiding from the bullets and won't expect you to come bursting in guns blazing
Place your shots carefully and step lightly but quickly
Always remember to use "mercy" when possible. If you don't know what this is, basically when you come up behind someone on the other team, and they are not aware of you, you yell "mercy!" and they can stand up and leave the game. If they turn around to try and gun you down, you freakin blast them to kingdom come
Move and coordinate as a team, none of this call of duty lone wolf bullstuff. Keep sitreps of where you are moving and where the targets are at all times. Maybe get some hand signals established before hand so you can communicate without using your voice