This past month I've been going to life drawing sessions with long poses. I think I'm finally making some progress. I did this one today.
Here's a tip for you: use bigger, opaque brushes. As big as you can fit into the task of marking a particular plane. The streaking you've got - most noticeable on the thigh and upper arm - doesn't describe the form or lighting, it is just distracting. Were you to paint these parts with big brushes, you'd have to think about the form, not about applying color, and they would come out better.
Nice color in the flesh tones. Long poses are good...I know my own skills improved tremendously when I started working from longer poses. Two thoughts:
1. The anatomical proportions are a bit dodgy, and that unfinished left hand is really distracting. If you've got three hours, you might want to spend more of it getting the drawing right before you start in with the paint.
2. You might want to focus on using the direction of your brush strokes to define the form....this is especially important when you're using a Wacom tablet, since that doesn't allow the calligraphic quality you can get with an actual physical brush. I think this is what Arenhaus is getting at, although I don't see that using bigger brushes would make much of a difference. The general art-school principle is that painting "across" the form defines it better than painting "along" it. JPEG attached.
As for using bigger brushes - it's about thinking in terms of form and planes, instead of trying to fill a blot with a small brush.