That is pretty impressive, especially for having done it all manually! You might try Ascension's Swiss-style relief tutorial: http://www.cartographersguild.com/tu...f-shading.html It's fairly easy to adapt it to an existing shape, and it give decent results. At the very least, it might provide a springboard for you to build from.

And welcome to the Guild! Have some rep for jumping right in with a map.