I’d replace the first frost tower with another firebolt tower or maybe a bomb tower. Those could fire onto an earlier part of your path, in a similar way as your existing firebolt tower.
Also, consider moving one tower to the free top-left spot inmidst ruins.
If you can, the spot diagonally left-below the big area in front of the castle gate would also be a good spot for some tower.
Placing a firebolt tower somewhere where it can fire across the longes overlapping path area might be good for taking out cannons.
Though, with the high amount of path overlap your wave troops could also deal with cannons… some pyromancers can devastate cannons pretty well… anyway, my only big “rules” for waves are “1 froster per wave” and “path overlap -> use ranged troops; no path overlap -> use more melee troops”.
In the bottom-left (right above that ruin), would be another spot for a long-ranged tower. I’d suggest moving around some of your barricades/blockades. Currently, 5 of your 8 obstacles can be hit ahead with spells or ranged troops before the king actually them, so those don’t work effective where they are. In the beginning, there are no obstacles at all, that’s where I’d move at least one of them.
Also, I am not sure how well your frost and gargoyle towers work in the corners - there, king and many troops can easily skip past them without taking damage, but that depends a bit on the attacker’s troop combination and raiding style. Anyway, putting together 3 towers into one corner is not good as they can all be hit with a single spell, so you give the attacker the opportunity to do much damage to your defense with a single spell.
Still, nice design.
And I guess your main intentions were 1. concentrating fire tower in the middle section to possibly kill attacking kings, and 2. leaving the beginning empty to make attackers deal with your first troop waves first before even destroying your first towers. Also, your layout with many bomb towers in the central area might kill many troops and distract the king if he tries to throw back some of the bombs… meanwhile the firebolt tower will fire across path overlap to hold back the raiding troops, while your defensive ranged troops can attack hero and support the firebolt tower…
One thing for getting an impression of your base’s strength is looking what were the king levels, trophy rankings and troop/spell combinations of attackers that are able to defeat your base. If most of your attackers don’t get over 75% at your base, then you’re doing pretty well currently, same if only stronger/higher-levelled/ranked players dare to attack you.
Biggest tip: Unlock the 3rd spell slot as soon as possible! It is probably the most valuable unlock in the whole game.