As both a model and a photographer, I can tell you that there are two sides to taking a good portrait, the model and the setup.
In your case, since you would be considered the model, you want to make sure you're posing well. You can find a variety of good poses here (
http://digital-photography-school.com/2 ... aphing-men). Also make sure you read Chase's new article about facial expressions.
As for the technical side of it, the two biggest factors are the composition and the lighting. For composition, make sure you understand the rule of thirds and how to use it. There are other methods, but that one is the most common. As for lighting, you want to make sure you're either using very soft light from the front or hard back light, depending on what look you are trying to achieve (the second is most effectively achieved in the studio as that kind of light is hard to find in nature). This website should give you a decent understanding of how to use different light sources to get the look you want (
http://www.cambridgeincolour.com/tutori ... ghting.htm)