Frustrated - W.I.P.

So I've started my pre-selection kits for uni. I've started digitally painting a landscape and here are the working progress pictures. Obviously it's still not finished, but it's frustrating me because not only am I lost when it comes to landscapes, but I don't know what to do to make the cliffs look like cliffs (rather than weird smooth things) and make everything look more...substantial. Anyway, I've decided to give it a rest for a night and worry about it tomorrow.

I also need to design a signature for myself to put on my work. So much to do :)