Those lakes are pretty huge for having no inflowing rivers worth showing.

The land shapes themselves are pretty good, but crowding so close to the edges of the page still gives a taste of "fill the page syndrome". If the island were move a bit to the right, and sea allowed some space around the sides of the map, it would look better. Of course, if this is for your own reference only, then that doesn't matter so much.

You have a river violation (or a canal in a very odd place) running across your island. Rivers do not flow sea-to-sea.