Town Hall 8 is where base design starts getting fun. Whilst it is impossible to design a TH8 base that a TH8 attacker can't take down, you can make it difficult. A successful TH8 base will either draw several TH8 attacks before getting three starred, or even force a TH9 to drop down and clean it up.
The three most common attacks you'll see at Town Hall 8 are Mass Dragons or Dragloon, Mass Hogs, and GoWiPe. These are the three attacks you should focus on defending against.
We have quite a few TH8 designs that work well for us. If you need advice or would like to use one of our good bases, let a Co-Leader know. If you'd prefer to design your own though, I would encourage it. Thinking about base defence will also help you learn how to analyse and break down enemy bases.
The bases below are a few I saw and liked after a quick Google image search (posting our own bases online seems foolish). Note all the bases are quite symmetrical. This makes it easier for attackers to anticipate how troops will path through the base. Consider adding some asymmetries if using these designs.
This base has a nice anti-dragon design. The air defences are well protected by high HP buildings and the clan castle is hard to lure. Junk buildings are protected by defences, so there is nowhere easy to kill the clan castle troops. It does have a number of weaknesses though:
Modifying this base to eliminate these flaws could result in a strong war base however.
This base with looks potentially quite strong. It is nicely spaced out and has lots of compartments so will be difficult to GoWiPe successfully. In principal it could be hard to attack with hogs and dragons too. Whilst it has quite a few weaknesses they could be easily corrected:
Obviously the bombs and traps still need to be positioned, but this base looks pretty strong to me against all three attacks. The clan castle is difficult to lure, the ADs well protected by high HP storages, and it is nicely spread out with plenty of good trap positions to defend against hogs. I would consider: