I haven't looked at books for a while on this but I remember Kodak's Portrait book with the little girl on the cover leaning on her hands was not too bad. I'll have a look around at a couple of books stores and get back to you. You need books that show different setups and diagram their lighting. Then you get a model that will sit patiently while you tinker around. It's not a good idea to get someone new as they will make you nervous. You just need a face that you can take your time and watch the lighting patterns on their face.

To give you an idea when I was first training in portraiture, and I took many different seminars and courses in this from many different instructors
(Winona School of Professional Photography, West Coast School, etc) the best advice I got was the following.

Facial Evaluation- Sit the subject on a stool, sitting up straight, feet flat on the floor, facing straight ahead. With no lighting on them you evaluate their face to determine things like, where their hair is parted, because if you shot them from one angle and you shoot into a hair part, you are making their face longer. If they have a round face you probably want it longer so that is a good way to shoot them. If they have a long face already, you want the part more away from the camera. You them get them to turn their body 45 degrees and turn their head back and you evaluate, then you get them to turn the other way 45 degrees and turn their head back and you evaluate that. Nobody's face is perfectly symetrical and you check the distance from the corner of their eye to the corner of their mouth, and if the difference is noticeable you pick the side that doesn't accentuate this. So evaluate. Then you pick the side you like best.

Lighting Setup- Now you have them on the side you want, you choose whether to broad or short light them, meaning, if they are turned to their right with their face towards camera, and you place the light on their left side ( camera right) you are creating a broad light. This will broaden the face because the light is illuminating their face from their left ear to right cheekbone. If you place the light on their left side you have a short light and will keep their face more narrow because the light is illuminating from their right cheekbone essentially to their left cheekbone and leaving their left cheekbone to their left ear in a more shadowed light.

In all cases you need a fill on the shadow side to lower the contrast and when using negatives, meter more for the shadow side.

This evaluation will give you time to talk to them and help make them at ease rather than immediately pulling out the camera and firing away. As well it will give you a starting point and these simple decisions can have a great effect on the flattering effect of the portrait.

Remember lighting a face is like making love to it. It need to be soft and sensuous,(usually) so you light it like you're using a feather not a sledge hammer.

Hope this helps

Michael McBlane