Here's what I started with, and it depressed me a lot to realise I had to practice.
Next I did a concept sketch making it a little more 3d after watching a video on how to do concept painting... and then I realised it was a long way from here to what I wanted.
Then attempt number 2.
Finally I felt brave enough to sketch something more adventurous. I copied this from a book by Marc McBride. A book on drawing epic monster battles. I'm happy with the result, but the adventure has just begun.