I think that really depends on who you are. There are a couple thing I think each winning alliance needs to do. 1) DAMAGE every defense (ie. cross it twice) to this end. teams may want to chose partners who can breach the defenses that they themselves cannot breach. 2) weaken the tower (put 8 boulders in it) teams may not specialize in putting boulders in towers, if an alliance captain is not good at putting lots of bolder in towers, then they may want to get a partner to weaken the tower just by putting a large volume of boulders in it. 3) capture and climb, this is all just points, if you can climb you virtually guarantee your alliance 15 points, this makes you very attractive