Ok I downloaded the world and these are my tips

Use the same blocks for your outer walls and the castle itself, it will look a lot better, and try to make a real castle gate. not just a wall with a door :P

Try to fill up your garden, it looks so empty. like a little lake or something with some trees.

and the last thing, try to make it bigger and add some more details. show me you really did put effort in your builds.

and what I love is the overpass between the towers ! good job, you earned yourself a diamond :)