You can start here and try to download a picture and it will make a chart for you. In my experience, they're not always clear, but it can give you a background to refine.
If you have a picture, you can put the graph paper over it and trace--hold it on a window for the light to come through. Or, if you can transfer the graph paper to a transparency, you can put that directly over the picture.
Or you can break out the colored pencils and try it freehand.