Step 1- Scan the drawing. This was drawn on newsprint paper, with a B pencil. Just a loose sketch, that was what I was going for.
Step 2- The original scan was not dark enough, so I darkened it by duplicating the layer and making the new duplicated layer a "multiply" layer.
Step 3- I added some white highlight areas with a photoshop brush on a new "lighten" layer.
Step 4- I added some dark shaded areas with a photoshop brush on a new "darken" layer.
Step 5- FINISHED. I added a texture layer on a"multiply" layer. There was already a bit of texture in the original scan from the natural texture of the newsprint, but I wanted it to look old and worn at the edges.