Welcome to the guild Kazy.
To give an impression of a higher elevetion like a plateau, here are some example
http://www.cartographersguild.com/tu...-tricks-5.html (post 41 and 44)
How did you make you trees ? Be cautious how your elements overlap when you place them or select the option in the layer window to keep transparent pixels intact. or even better, change the mode to background ? (it should be in the first section but I'm usure since I don't have the english version). It will allow you to paint under.
I think your font should be plain, try putting it to bold maybe?
By the way, your background is a little psychedelic.