The first thing that jumps out at me is the artifacts from jpeg compression. I'll bet if you save it out again with a quality level of 80 - 90% it will look much nicer. I'm guessing this one is around 50 - 60%? Jpeg doesn't like areas of flat color very much, which is interfering with the clarity of your coastlines.

I don't know how you're approaching your shaded relief, but if you're doing it with the overlay and dodge/burn trick, put your relief layer above the trees--that way the trees will appear to be on the slopes also.

Beyond that, I agree with Ravs: some variation in the sea would be very nice. Make it subtle, though--you don't want the water texture to overpower the details of your land.