Here is an analysis of x_addict_x's base. This is an excellent example of a really effective defense and this base is quite similar to my own. You can click on the picture to get a larger image.
1. Cleverly placed firebolt towers.
In this picture of the defense, the yellow circled firebolt towers are really well placed, and are very difficult to remove before they do serious damage. They will efficiently mow down invading forces while lying beyond the hero's reach. The only effective ways to destroy them is by either going solo with the king through the base until you reach them or by using cannons. If you use cannons, they will likely be destroyed by the firebolt tower in the process of taking it down, and going solo with the hero tends to be quite perilous. Ensure that you place your strongest firebolt towers in these kind of positions.
2. Utilize the Corners
Firebolt towers like the left-uppermost red-circled firebolt tower are also really well placed as they sit back from the path and won't naturally be targeted by enemy pyromancers. This forces the enemy hero to go further out of their way to deal with them, costing them more time. By moving the red-asterisked firebolt towers into similar positions after removing the ruins, they will become much more effective. The uppermost red-asterisked firebolt tower would be particularly effective if it was moved down a place as it would be able to target the region in front of your snake tower, making it all the more effective. By spreading your towers out like this, you will also further delay the enemy hero's advance to the second choke point, making it all the more effective.
3. Protect the gate
The rightmost red-circled firebolt tower is also really well placed. These corners in front of the castle gate are a really good position for firebolt towers as firebolt towers will be able to target the enemy hero before he even enters the six squares in front of the castle gate and set him on fire. This prevents the enemy hero from healing and does potentially fatal DOT. This tactic is actually really effective against those heroes that have made it through the rest of your base and are on low health, and often prevents those who are not careful (most players) from advancing to and destroying the castle gate.
4. Venomous bite
If you are going for a deathtrap style base, consider replacing your second skull tower with a high-level snake tower. Since a recent update, the snake tower does much more damage to enemy heroes and will effectively erode their health. By alternating damage types like this, you can ensure that the enemy is both on fire and poisoned as much as possible, and this serves to kill them more quickly.
5. Well placed barricades and traps
Most of the barriers are really well placed and are spread out so that they can't be taken out in a single bladestorm. I particularly like the placement of the orange-circled barrier as it delays and bunches up enemy troops so that the first skull tower can be used to full effect. The first barrier also has the really valuable role of delaying the enemy hero by a couple of seconds, giving the first wave of troops time to make it over the second barrier on the path. Most players would imaginably use their spells on it and be unable to destroy the second barrier immediately. This forces their hero into a brawl with the troops that just made it over the second barrier while being gunned upon by the red-circled firebolt towers.
Only the purple-circled barrier is badly placed as it can easily be taken out by a bladestorm as the enemy hero walks along the other side of the path. This is largely a consequence of there being a lack of a better place to put it though. Perhaps if your first skull tower was of a really high level, it would be better to place it at the start of your defense to allow the skull tower to be used to even greater effect?
Overall, this is a really good base and there are very few things that can be improved. If you have any questions or comments about the article, please feel free to post them below.