I won't go to much into details but just recommend that you team up with a friend and then start to play with light setup, modifiers, gels and positioning of the model in the surroundings you have chosen. It's lot of fun.
Nikon D300 with Sigma 70-200mm f/2.8. Exposure: 1/40 sec at f/2.8 (ISO 400)
The first photo is SOOF - Straight Our Of Camera - no post processing in LR! It just shows how well a photo can be done "in camera" if all settings are correct. And light plays a major role in getting a photo sharp also. I have added no sharpening at all. And this is captured with a Nikon D300 - (12 MP sensor!) at ISO 400.
Nikon D300 with Nikkor AF-S 12-24mm f/4. Exposure: 1/60 sec at f/8.0 (ISO 400)
The second photo has been post processed a bit in LR3. I've added sharping and noise reduction together with some clarity. That's all.
With both photos I find that the light is falling just right (SB-900 with a 1/2 CTO reflected from an umbrella) adding nice shadows and the 1/2 CTO is adding a nice warmth to the skin.