Generally I'll go after the builder, since if I go after the builder he'll run, and both the knight and archer are going to follow me. (Most likely, at least) Whether I live or die trying to kill the builder, I'm pulling their whole front line back and giving our team ground. Then our other knights/archers that can meet the enemy farther and farther out, and it's safer for our builders to build nearer walls, mine in more places, and push our territory out and closer to the enemy.
Feel free to start this fresh in a new thread, I hadn't planned on a series so if it could all be archived in one thread that would actually be better. Do you mind if I contribute now and then? :)