The Sketch
I use a blue pencil to sketch out the basic shapes of the image. At this stage, I do not worry about how perfect the drawing is. I just want to quickly sketch out the subject with a light touch. The last thing I do is block in the areas of shadow. This step in the process shouldn't take more than 5-10 minutes. If it does, it it possible that you are trying to finish the painting before you even begin. Keep your stokes fluid and free. You can always paint over any stray lines later.