A quick follow up with a list of things that we have seen tried and that don't work time after time.
Bunching up. Especially multiple players behind the same piece of cover
Guarding the flag. This is a fired up bunkering waiting to happen. Give yourself the option of moving.
Lone wolfing it. Either another lone wolf will get you or you will get him but in most cases even if you create an opening there will be no one with you to exploit it. Most of the time you will not win every game by yourself.
Playing the "waiting for the other team to come" sa-tragedy HA HA! All this does is delay the inevitable.
Second wave. Where a few guys let the front wave feel out the enemy and get killed. If you didn't see the enemy you don't know where they are. Maintain contact with the enemy and keep the pressure on. Wait for them to make the mistake. Use it against them
Don't play follow the leader. If a guy habitually goes off on his own and does get some occasional success do not try to tag along with him. He works best alone and likes it that way. Going with him is going to ruin his game and you shouldn't try to leach off of his play. Unless he asks you to.