Not every drawing flows magically out of my hand, sometimes the idea in my mind gets stuck somewhere inbetween my head and hand and I get lost. It's ok, because I just pick up the pencil and keep trying until I'm satisfied. Sometimes it takes more effort to get something right, other times it just happens.
A couple days ago I did a quick sketch of Jack, and at first I was happy with it, well for a quick sketch anyways, and the more I looked at it the more something about it bugged me. I couldn't quite figure out what it was. I posted it on a couple forums so my colleagues and friends could see it and they too saw something off with it. That's ok, it happens, it's a good idea to let others with fresh eyes see your work, it helps to see your work from another's point of view. Anyways, I went back to the drawing board today and had another go at Jack, I am pleased with this version and I feel a weight has been lifted off my mind . . . whew!