
Here is a photo that I did with a simple two light scenario. One huge softbox up high and another aimed at the background behind the model ...exposure was f/8 at 1/200th ISO 100
Studio lights rock!
These lights (monolights) are big in comparison to normal flashes and the size is shown in the power they put out. I hate when i have to wait...especially for small flashes. With the studio lights on the other hand, the power recycle times are so short. This allows the light to be ready quickly for the next shot so you don't miss expressions from you model.
Relax!
I find that taking pictures of people is more about getting them to relax than anything...Sure, you have to light the scene and make them look good, but if they're uncomfortable this ain't gonna happen. I like just talking to the model, reassuring them the pictures are coming out well even if I know there's something wrong. I've been reading a lot of Joe McNally's new book and even in there he explains this. Many times I'm behind the camera and I'm thinking "Do I really know what I'm doing?"..."Is this going to work?"..."oh shit!, Is this thing on?"..."lens cap idiot...take off the lens cap!"...once your internal monologue goes public it's over. They are looking to you to make them feel confident and that their pics are going to be awesome. If they relax it's easy to get some great expressions and get a glimpse of what their personality is like. Just relax and they will too...

I use a large gold reflector to bounce light back up at the model. Some people call this clam shell lighting; One light is directly above the camera angled down and the reflector is directly below angled up creating a "clam shell"...easy lighting technique for portraits
I hope this helps and if you want a head shot, let me know :P