Lighting man. You need lighting.
Your subject will not be adequately lit without having hot lights or off camera strobes. Hot lights are the cheapest, but in order to have those running you have to have a generator which is not the cheapest. If you can find a way to get a power source, picking up one or two 500w lights at any hardware store would be a great investment for photography. Your composition is ok, just remember to aim a little more for the corners. Look through Erik Seo, and Mattias Fredriksson's portfolios too, they consistently kill it and you can learn a lot about where to place the action by looking through their portfolios.
When looking through, ask yourself "where is the subject" in relation with the frame of the photo and then ask "why does it work". Keep it at man!!!!