When you make small gaps like on the top of it, you should make them bigish, or not at all. Small extrusion are a waste of time because you won't notice them. Needs to be less blocky. The top "gaps" need too be bigger, not in depth, but in space between them, if you get what I mean.

I will stick it in paint later and show you what needs changing, im going out in 15 minutes now though.