im suprised that none of you have mentioned wet sanding. Its a great way to remove imperfections.
Dont go to kmart or wal mart - go to an auto body supply store for this stuff.
Clean the paint really good first.
Most scratches and large imperfections can be wet sanded out with 1500 and 2000 grit on a foam sanding block. Just be careful not to sand through the clear coat.
Follow up by using a cutting compound and polish on the entire car to remove all of the spider webs and swirls. Be careful around ridges and body creases (like on the hood and sharper fender creases) so that you dont burn through the paint.
After you have polished out the paint wax it really good..
Wax is only as good as what is underneath it. If you wax over the crappy paint then it really wont help you out. All wax does is coat the paint.
You can do this same process to your tail and side lights to make them look new. Just be a bit more careful with the rubbing compound because you can melt the surface of the plastic if you press too hard or turn it up too high.