http://www.youtube.com/watch?v=wSDDTLt75Bk

This video is a great way to do mountains. I suggest drawing a more detailed mountain than in the video though. Look at hte ystraad map for a good example. The Valcano Island looks great. The only area that makes me not buy into the realism is the placement of the landmasses. It looks a bit even or something. Other than that it looks like a great start to me.

Good luck with the world,
Robb