it seems to me you have some problems with the basic structure of the stones. The 2. vers. is way better, but there are stil alot of issues.
I was bored so i did an edit
step 1: Split the suject you wanna dew into specific defined tiles, it'll help you ensuring they'll actually be tilable
step 2: The 4 left (and right) right tiles are special cause they have to be combinable with both them selves and the middle fraction. In this case, the easiest way to go about it, is to make sure they can be combined with itself. This can be a bit tricky, but you'll quickly get the hang of it. Also, when you draw the stones, start at the bottom and work your way up, it'll create a somewhat beliavable structure.
step 3: Repeat the step above on the right part
step: 4 I accidently deleted a step, but doing step 2 and 3, you have the lines on both sides of the middle part. Fill the middle tiles with stones and connecting the right and left part. The left and right tiles are now tileable with them selves as well as the middle.
step 5: Start shading the bastard (actually i fucked up here, it's better to block out the basic coloring), stay away from the extreme right and left stones! I advise you to try replicating the style of his stone on a much smaller scale. Don't stop tilll you confident you have it, and you'll saveyourself a LOT of trouble when you move on to the actuall cliff structure
step 6: Copy the 4 left and right stones to the places they'll have be when there tiled later on, now start shading the blank places away
step 7: Dew your final touchups
Notes: there are some issues with my edit that I don't bother change, but you should look into. The main prob. is the lack of vertical contrast between the bottom and and top of the stones (like this
http://www.inventiveminds.dk/vedsten/temp/mockup3.gif) I tried fixing it in step 7 (with low succes), but really, it would've been much easier doing it in step 5 (blocking out colors)