Mostly what you have to do is talk to your subject. Work your interpersonal skills. Learn some things about them and get them to laugh. It's hard to do in a matter of minutes and sometimes it doesn't work at all. I have had shoots where I nailed the shot in 10 minutes and then turned around and worked for 3 hours and not gotten it. And when a subject is just not working with you you have to know how to set them up to take a good portrait anyway. The best thing I can tell you is get everyone who will sit for you to sit for you. Practice, practice, practice. There is a lot of different things that go into a good portrait. First I would start with natural available light portraits. Get those down and move on and modify those. Learn to separate your subject from the background. Studio lighting is a whole other realm of photography, check this book, Photographing People: Portraits - Fashion - Glamour . I am no expert with studio lighting by any means but if I had a studio to try the setups shown in this book I would.