I agree with most of what Chris said above, however there ARE ways of using paper to stabilize your block and improve accuracy without actually sewing through the paper, which is the part of paper piecing that a lot of people dislike. I prefer to use the fold-and-stitch method of paper piecing, with vellum as my paper.
Your best bet, if you're a beginning paper piecer, is to check YouTube for videos, or see if there's a class in your area, or maybe even check around at your local guild for "paper-piecing queens" who would be happy to show you how it's done. It's much easier to grasp the concept and learn the skills by being shown, rather than trying to read written instructions.