Great start Killer, your drawings look a lot like mine. My art teacher tells me over and over again to try using more texture and value in my drawings. I can’t stop doing contour drawings though. Try going over your lines once in a while to make them darker, go over them in strokes. Using contour to get the basic shape is good, and you seem to have a great grasp of it. Keep it up and try using some more value!
Do you want to run a stake through the heart of your contour drawing? Try drawing with a piece of wadded up chamois (you can get it at auto parts shops – used for drying cars) and a block of charcoal. Cover the entire paper with charcoal, then wipe away the lighter parts with the chamois. When you need to add more dark, you can’t use the corner or edge of the charcoal block, only the side. Works wonders for getting rid of those nasty edges and contours.
Ya, I have to agree with Wonderlust, you need to get some value in there. You have good form and everything, but value is really what brings an image out. When you look at something, it isn’t just flat, it has depth and shading to it. They’re good starts, but I suggest you add some detail to them. Have you had any art classes or anything? 7 years seems to be a long time with out learning to do that kind of stuff and improving on it.