try and envision each troop and how it would behave as it attacked your base. create a spot that intentionally looks inviting to attackers. that will narrow down likely spawn points. then build your base to use attacker AI against itself, guiding attacking troops into traps and choke points. basically, don't think like a defender, think like the attacker. that way you won't be concerned with things like symmetry, closing all of your walls so that there are no gaps (you want gaps, trust me), or surrounding your resource buildings with defensive buildings on all sides. You're looking for asymmetry, creating bait and traps.