This is an opinion thing. Some of you may comepletely disagree with this and some of you may agree with this.
My first tip is to put traps. Honestly, this is one of the best ways to prevent 100% raids. PLACEMENT: Pick the side where you get attacked the most. On that side, right outside the walls or farthest outer buildings, put small bombs and spring traps. Also Make sure there is an air bomb covering each side of your base. With the Giant bombs, put them near your Town Hall along with any extra spring traps and bombs. Your Teslas should also be near the town hall.
Air defences should be parallel to eachother, covering the whole base. The main thing with Cannons and Archer Towers, Make sure they are also paraell to eachother. The more Symetrical your base is, the more well rounded it is. Mortars should be in the middle of the base along with wizard towers. OVERLAP DEFENCE RAIDIUSES! There is a spot in my base where 11 defences can attack 1 target on top of a giant bomb. Any troop who enters that area is screwed most of the time.
The last tip is divide your base. The more compartments, the better. When all your things are in one wall compartment, all you need is one wall breaker and say goodbye. The walls will stall a lot so your defences have plenty more attack time. Oh and personally, I think putting builders in the corners is dumb. Most people will scan the whole base and instantly you have percentage against you that could be the difference between a win and a loss.
I will post a pic of my base soon but for now, thanks for reading.