At Town Hall 7 your base is going to get three starred every war. Don't sweat it. Town Hall 7 bases are easy to three star even for Town Hall 7 attackers. The best you can hope for is to fend off some weak TH7 attackers and force a TH8 to drop down to clean your base up.
The example base in the picture is one of Dokugan's TH7 designs. It has a few flaws (no air sweeper as it is old, Barb King doesn't achieve much, black air mine should be near an air defence to take out the first dragon that gets near) but is a nice illustration of how to use high HP buildings to protect air defences, and has a nicely centred clan castle.