That's a great start, what software did you use? I like the rough mountain texture.
Couple of comments (though admittedly I'm no master mapper)--tone down the bright green on the coastlines just a tad. If you're using photoshop, you can use any number of adjustment layer options to help with that (saturation, brightness/contrast, etc.) along with a layer mask and it should do the trick.
I thought the green "hole punch" fill you used for the forest texture was a bit distracting; maybe look at a different type of fill or brush for that?
I really like the shoreline work you've done, but I agree on toning down the brightness. It hides some of the details that I'd like to see, at least to me.
Looks like a very nice starts. I enjoy the colours and the overall shape of the landmass.
As previously mentioned, perhaps a toning-down of the coastal brightness would be in order.
Also, there are some minor river issues:
-In the bottom-centre, there is a small peninsula being crossed by two rivers that could not properly happen unless under very specific circumstances (such as them being tidal canals).
-On the centre-right side of the map, there is a lake that is draining out through two separate rivers that are very close to each other. There should be only a single river.
-On the centre-left side, there is an upward-turning peninsula with a couple of very odd rivers, movng both across the peninsula and in parallel to the coast. As above, unless these are very unusual tidal canals, they should not work as rivers.
In any case, the three are very minor details, and you have a solid base here to work with.
Interesting, the contrast with the mountains is better, the "glow" around the coasts is lowered a little bit too, though I might try and lower the contrast even more.
I wonder if going with just a slightly more subtle hue of green from the forest, rather than such a radically different one might work better?
For the forests, from what I can tell the problem might be that the brush or texture you've chosen has a lot of linear / straight lines. Something more rounded / curved might work better?
Overall I like the general vibe and concept a lot, though. It feels . . . kind of wild, and savage, a bit mysterious.
Which elements are you using with Wilbur?