I think that the best think to do when your at a stage like this in your art is to dance with your realism shoes for a while. A really great book you could pick up from the LIB is Drawing on the Right Side of the Brain. It's an exceltent book that will help you render objects and people as they appear. Realism is a nessary stage for any artist.
Keep working on your other arts on the side, but work hard to draw accuratly what you see. Most programs for this take about 3 months to complete and by the end you won't beleive how much you'll improve.
More exactly with your drawings. I notice your waist line rises and falls like the tide! Try laying donw a manikin type sketch before you start a body. It's like training wheels to stop you from slipping off track.
My favorite human body tutorials.
http://www.deviantart.com/deviation/36369693/?qo=56&q=by:kitten-chan&qh=sort:time+-in:scrapsThis girl happens to be one of my fav artists, and she's layin it don't tight in this tut. Really, for the basics, this one's great.
But...
If you ever have time and wanted to move a little deeper into anatomy
http://www.deviantart.com/deviation/15014442/Cedarseed is the god of online anatomical guides. If you want to really pimp your skillz, all his tut.s are to die for.