Car Upholstery: Do it yourself interior, contact cement, interior fabrics

Question
I would like to cover some of the interior fabrics in my 01' Cavalier Sedan. How difficult is it to recover a headliner? Can you leave the original on? As far as door panels, what is the best way to go about recovering them so they look professional? What kind of adhesive do you recommend for these projects? Can I use any kind of fabric? Do i need to put anything over the top so they stay better?
I know this is a lot to answer, I appreciate any advice you can give me.
Thanks!

Answer
Headliners are easy but time consuming. Remove trim holding headliner. Carefully remove headliner. Pull off old cover and scrape off foam with a wire brush (especially bends and corners). Using contact cement (a light coat on each side, allowing it to tack) stretch lightly starting from center ,working to the corners.With a flat hand, press smoothly to stick new foam to board. I fold the edges behind and glue to the back of the headliner board. There are no edges to show.  Reinstall. I would have to see the door panels to advise on these. Use automotive quality cloth and contact cement or a high grade trim adhesive only. I do not know what you mean by something over the top. rim should be fastened firmly. Mark.