Welcome to Town Hall 7, the first Town Hall level where strategy really starts to come into play for many users. Players enjoy attack upgrades with the dragon and Barbarian King.
As a TH7 attacking another TH7, there is really only one go-to Three-Star strategy, Mass-Dragons (aka Drag). Dragons are the most powerful troop for a TH7 and with weak air defenses at TH7, it should be your one and only option. However, it is not as easy as it sounds.
To perform a solid Drag attack, TH7 players need to fill troop capacities with all dragons, request max balloons in the clan castle and bring three lightning spells. A typical TH7 is below.
On the specific base above, players should use all three lightning spells on one air defense or the other. I always prefer to take out the one closest to the middle of the layout. After taking out one air defense, place one dragon on each corner of the side you are attacking. Wait for your two dragons to do some damage (about 15-20 seconds) and unleash the rest plus balloons in between the two and enjoy destruction.
The toughest part about the attack is waiting for the two dragons to begin what is called a funnel. Dragons will always target the next closest structure and can get messy if a proper funnel is not created.