A good base is important for defending your base. Without a good base, you can be easily defeated, regardless how strong your defensive buildings. For example, if you separate your maxed defensive buildings into everywhere, you can be defeated by a town hall 7 player.
Things Not to Do
Rectangular like Base
Never place all buildings together forming a rectangle without planning, and surround them with walls. Walls are supposed to slow down enemies, but in that base, there is only one layer of walls. Therefore, you cannot slow down enemies that much. Besides, without walls between buildings, enemies can easily walk from one building to another one. It decreases the difficulty of the raid of enemies. People uses P.E.K.K.A or giants to face this kind of base.
Filling the Whole Village
Every clashers should know that there is no meaning on filling the entire village area with buildings and walls because enemies can deploy troops outside of the board.
Exposed Town Hall
You should not put your town hall outside of your base, no matter how powerful your traps are, including hidden tesla. People can use barbarian, Archer or minion (not for triggering air mine) to trigger all your traps, or use wizards to clear your hidden teslas, and attack your town hall. However, in some cases, exposing your town hall is a good idea. Details below.
Tips and Tricks
Anti Hog Rider Base
You can make an anti Hog Rider Base by considering the defensive buildings as a path. The goal is to lead the hog riders to a Double Giant Bomb Area without having too much defensive buildings down. Make sure that your base can lead hog riders to there, regardless where the hog riders from.
TH7 Wizard Tower + Giant Bomb
When hog riders reach a giant Bomb, they will be in low health. The wizard tower next to it can clear them with a few hits. This method can take over the double giant Bomb.
I mean incomplete Wall by having a hole at it. Filling the hole with traps is useless. If you really don't have enough walls, unprotect a building and use the walls left to fill the hole.
No Traps Near Clan Castle
It is not recommended to set traps near the clan castle, because players may deploy a barbarian or an Archer to lure out reinforcements, meanwhile accidentally triggering your trap. That trap would be a waste.