A suggestion: I'm not sure what medium you're working with, but I might suggest working with soft charcoal pencils. The medium is a lot more loose, so you might have an easier time forming tones as opposed to hatching the shadows like you are. Also, if you're working with a model, doing some quick, 1-5 minute gesture drawings of the figure will help you warm up for a longer pose. You can do this working from a photo as well, but drawings always seem more dynamic when drawn from life.
Oh, and don't avoid the "naughty bits" of the male model. May as well make him complete!
You're improving every time I peek in here. Keep it up!