DOnt suck at map deisgn means :
Mix terrains, grass/ sand/ grass-sand/ ice-grass, etc. Just having a single terrian at a place over a large area makes the ground look dull.
Mix elevations - all greography in the world has mixed elevations, a flat surface in the map once again looks less appealling then mixed-elevated surfaces. AoM dos the job easier for you through Roughen and Smoothen tools, so use them.
Trees - Dont just make a large clump of trees, and if possible dont make them too close and nearby either. Separate them a bit, add flowers there, grass, bushes, mix the terrain there as well.
Eye-candy : AoM offers good eye-candy oppurtunities, Use them wisely. Have rocks at river side, in roads, mix the trees, add pots/flowers/barrles near houses, use move-object tool to create spectacular new things.
Water - After using the beautify tool, which makes the water look wuite a nice, place some more rocks, trees, terrain mixing, mix them underwater too.
Can you do the Double Yoda?
A sexual move, where you do a double backflip, insert your penis into the orifice of choice, and scream, "Afraid are you?"