I like Meguiars Ultimate Compound with a orbital buffer. Cheap, available at WalMart/Target, works very well, is very easy to use even if you have minimal experience and is very safe. Despite the name, it is a mild user friendly compound that breaks down to a fine polish, so it will remove scratches and leave a wax ready finish if you work it to a haze. It can be worked by hand, but will take more time and elbow grease...