One of the best offensive and defensive strategic advantages in the game is the proper usage of the Catapult.
Use Twig/Pebble Missiles/Bombs to weaken your enemies' defensive towers and save time.
Also, a great strategy to use when taking out your opponent's main yard is to use the 10M Putty Rage. It is very effective with a combination of Champions and D.A.V.E.s since they can wipe out most of the yard in few minutes. But every strength has its price, so use it wisely.
Also, when you hit a resource building with the Catapult, you will NOT loot resources, so don't hit Silos when you're catapulting, unless there are many important towers around it. It's just a waste. It doesn't make a difference if you hit a Town Hall, because a 10M Pebble Bomb can only destroy Town Hall levels 1-4.