Yes, the oil makes them shine, so now I'm painting darker shades of the uniform color into folds. Another thing you might try to liven em up is to take a lighter variant of the base coat (a light gray works wonders for feldgrau) and line edges of pockets, collars, etc. To make them look worn/frayed.
I've startedgetting serious about my figures, so any tips you pick up here, I might borrow!