Bubble Trap

A bubble trap is how you defeat an incoming stagger attack. If the enemy is sending multiple fleets but has bad timing, then you can bubble before the attack and have the first fleets bounce off the bubble. When you are sure you can win, send a scout to a nearby city to cancel your bubble and the last of the enemy fleets will engage in battle. You can zero an attacking fleet this way while not losing any troops. 

I had an alliance try this on my TA in another world where I am strong but I attacked last and ended up killing him in a 1v1 so don't bubble trap the wrong person! Make sure you will win the battle before removing the shield.