As a th8 you will want your base to defend well against the core th8 armies: GoWi, GoWiPe, DragLoon,Hogs,GoHo
There are many elements of a layout that can impact success or failure in defense.The following are those we deem as critical.
Against GoWi and GoWiPe the most important element of defense is to have many sections. The base should cause the golems to get stuck as early as possible. Non defense buildings should be placed so they distract wizards and separate them from the golems.
Against GoWiPe having teslas inside the walls and protected is also crucial. The teslas are the best anti pekka defense.
The most important defense against a dragon attack is the air defense. The air defenses should be inside the base, well protected from balloons or hogs, but not too close to one another. It is usually wise to have all 3 ADs in a triangle around the town hall to force dragons to go through the th while under AD fire. Once the triangle is placed in the base, observe the direction from which an attacker using DragLoonLight will attack, and place the sweeper against that direction. High hp buildings can be placed around the ADs in range to stall the dragons while the ADs shoot at them.
Against hogs the most important defense is the big bomb. It is critical to have 1 double big bomb inside the base and between defenses so the hogs step on it during the attack. All 3 big bombs should not be placed where they can be triggered by a single hog. The wizards towers should be inside the base in the second layer of defenses. It is often useful to have other high hp defenses such as ADs in the wizards tower range so they can shoot at the hogs while these are attacking the defense.
To prevent an effective GoHo attack, make sure there are multiple gaps inside the base that could hold double big bombs - this will mean the attacker does not know where to send the GoHo in from. If possible place the dbb on the opposite side of the base from the cc and bk.