I like the overall shape of your land mass, and the big wide river flowing into the middle in particular. Nice addition of small islands as well. Since you are using photoshop, may I humbly suggest checking out the Saderan tutorial (by Tear, found
here). It is relatively simple to follow, as long as you take your time, and gets some pretty stunning results, even on your first try. I'm currently working on my second Saderan based map, and loving it so far.
Keep working on this one though, maybe trying to redo it using the Saderan techniques. Very nice work!