Hello, I am doing cobblestone bases for my army, I got a plastic sheet that has the texture, I just can't figure out how to paint it. I have tried black then dry brushing on greys, I've tried washing, but I just doesn't seem right. Does anyone have any ideas?

I would have said black undercoat, drybrush dark grey, then 1 or 2 shades of lighter grey, maybe followed by a wash to bring it all back together would do the trick...Maybe a blue grey or a dark blue such as Asurmen Blue from the new washes range...depends on what colour cobbles you want though i guess...

If that doesn't work for you however I'm not really sure what to suggest - blending maybe or layering - would be a lot more time consuming to do it that way however...

If you showed some pics of your results this far it'd be easier to give some advice.
I would have used the drybrushing and washes technique though.

http://img411.imageshack.us/img411/8131/120807009vd5.jpg

This is a sheet.

Painted by a combo of washes and dry brushing. I left it quite muted, but you can always do more extreme painting.