If you want to improve your photography measurably and quickly, you are focussed and determined and ready for some hard but exhilarating work, I can recommend nothing better than to attend a hands-on workshop with a good teacher and other enthusiastic students. I recently attended such a workshop given by Neeto da Silva, a Toronto fashion and commercial photographer, and it was an absolutely wonderful experience. The workshop was tailored specifically to the students' needs, in this case how to direct and pose models to get great looks and expressions, and all the necessary studio gear was provided. We started at 10:00 AM and other than taking a few minutes to grab a quick bite to eat I didn't stop studying and shooting until 5:00 PM.
If you happen to be in the Toronto area and you're interested, drop me a line and I'll hook you up. All you need to bring is your camera, some suitable lenses, and your model release. In return you are going to have new skills, contacts and a much improved portfolio.