I'm pretty much self-taught and I think it shows, sadly. I was looking around for process tips and I'm pretty sure that my main issue at the moment is a lack of planning and groundwork.
JeffX99 made a very interesting post at http://conceptart.org/forums/showthread.php?t=220557 suggesting it is essential to work on thumbs then values then colour studies before even starting the full size image.
I also found Episode 17 at http://www.howtodigitalpaint.com suggesting a way of brainstorming thumbnails that appealed to me.
So, here is my attempt. I've only done the thumbs so far. I would very much like it if you let me know if there is one you think is better than all the others, and any issues you can see in its general form so far. I'll pick one and work on refining the form and then defining general values next.
The general theme is castles / ruins as I hope you can see.