I like to use backdrops! Because they make my map look more open, if I had a lot of high ends of the map, I feel like that would make me feel like I'm running around inside of a box. xD
When I use backdrops, I tend to add some mountain objects on the edges and trees, bushes, flowers in front of the backdrop. Not all the way though, just on some places.
I made a little map called The Valley where I used backdrops, I couldn't add too many objects because of my computer, but if you need an inspiration or just look at how others have done it, feel free to look around and get some ideas:
The Valley map.
Of course now that I look at it, there are certain things I'd like to change, make those backdrops a little bit smaller and stuff.