Well, I would say that your particular map is kinda tricky because of the angle. If you go top down then its not going to look high. I would just find an image that looks like the cliff you need and show your players and say you are looking at this...

Still, you can use cliff stamps. Whenever I go near to cliffs, water and rocks and stuff I take photos and chop them up.

Try these water textures :-
http://www.cgtextures.com/textures.php?t=browse&q=2194

then some cliffs...

http://www.cgtextures.com/textures.php?t=browse&q=2060

and try to combine them up. This is what I did in about 2 mins with stuff I had lying about.

Check out all of http://www.cgtextures.com/ as they have lots of stuff that can be clipped together to make some cliffs.