I want to draw a map of a fictional world resembling Europe in climate and basic geographic features (so there are rivers and lakes, alpine mountains, mittelgebirge, marsh lands and bogs, some plains and forests).
I am thinking of dithematic words (similar to typical endocentric compound words where the second part denotes the general feature and the first part gives a distinguishing detail), so I need words for river, lake, mountain, marsh, bog etc. and some determining words.
However, I want the words to look naturalistic and not overly schematic. What techniques can I use to make the geographical features look naturalistic?
EDIT: Assume that I have already designed a phonology for my conlang stub, and that I have already some phonotactics and candidate root words. What I am interested in is some natural looking variation of the names to generate.