equipment and location....
Not all of us can have a studio and a lot of equipment at our finger tips, if you don't have a studio think of taking shots of people in their natural environment or take advantage of the great outdoors or large open public venues with good light.
This page had some useful tips
Portrait Photography guide and tips from Photo.net
I particularly liked the idea of environmental portraiture - showing the subject in their surroundings. Concentrate on controlling the background amd focus the attention on the subject. Also control the lighting. If you don't have a studio or a vast array of background material, steal a location, use large picture windows or shopping mall lights to good effect. Make sure you flatter your subject by choosing the correct lens, a typical portrait lens is between 90-135mm. Having said that if taking environmental portraits you don't have to stick with this length of lens. Don't be afraid to use a fill in flash. Try to capture the spirit of the person and remember you don't always have to show the whole of the face. Last point....giving your subject space can sometimes give an image more impact.
All pointers to take on board.