Ok, start with the grass line. this does NOT go right at his feet, that looks funky. it goes about a quarter way up the leg, try to make it go straight even when you have to break the line for the legs, maybe use a ruler or a scrap of any stright paper. Here's how I want you to do it:
1. Start at one end. draw a line, doesn't have to be perfect, then stop, do only like a quarter of an inch to a half of an inch.2. then three or more dashes going up, don't have to be perfect, can come from the same point or just be all sitting there, whatever makes you happy.
3. now after a slight space start your line again. Do this over and over across the "grass line" of your image. Now everything above that is sky and below it is grass.
You can add some partial grass lines below the grass line for added depth.