Practicing drawing top-down hills - opinions

[Ilgoth]

Hey!

I'm soon gonna start my first large city map, and I decided to practice a bit. Here's the result;



Asked couple of my friends that is the inner grass area lower or higher. Four of them said it is higher and two said it is lower, so that made me worry - does this style work? I tried to give the sense of relief with two things; darker color of the cliff is outer so it's also lower, and then did that highlighted green on the edge of the grass. I think in digital painting this technique is called "rim lighting", but not fully sure.

Does this work? It only misses the shadow sun would cast on the other side of the hill.