i draw in photoshop using a wacom tablet
i make a new canvas larger then i plan my final picture to be, usually much larger
i draw the picture i want to draw using the pencil tool and my wacom tablet
each element is on a different layer.
i then add color using the paint bucket tool
i reduce the image down to the final size and save for web
that is it.
here are two photoshop files you can download and open in photoshop to understand betterback to pictures