should have a selection of grits from 600 to 1600. The finer grits are safer but slow.
variable speed buffer w/ foam pad and wool pad.
i like 3m perfect-it 3000 rubbing compound followed by 3m perfect-it 3000 ultrafine machine polish.
one thing i do is surround a larger imperfection w/ low tack tape. use a short section of paint stick for block. easier to control wet sanding small area w/ paint stick block riding on tape.
some small imperfections will buff out just like the salesman said.