I had some success with drawing top down mountains and making them pop out of the map. If you are interested head to my city Twin River. Check out the ones further down on the page. Exhibit A and Exhibit B

The important thing is learning to add Cast shadows for your mountains then Core shadows closer to the mountain foot and peak, nice and dark. Finally add Highlights on the other side. The highlights really are important, they do have a big effect alongside the cast and core shadows.

Like for example, if one only add the big cast shadows without the others, it would look like there is something there. But, it wouldn't pop. Adding the darker core shadows (A smaller closer to the object shadow- less light there.) it starts doing something. Then adding highlights bring it all together. Hope it helps a bit. Feel free to ask.