well i would do it like thius:
sand witha bog file, using corse paper, this makes the top paint come off and leaves where the dents are a different colour.
get your self some bog, (ALOT cheaper to buy ina 4 litre tin froma panelshop then super crap etc)
fill in the patches that are the original body colour.
get your bog file out again, start with a corsepaper, then move on to the fine 1 ( the paper comes in pack of 3, 1 super corse, and 2 not so corse)
then when your happy with ur body, get onto it witha 6 inch orbital air sander.
then mask up and paint with 2 pack high fill primer( this fills little scratches)
then give it a web rub and get into any little places that you cant sand witha scotch scourer.
then you give the whole car a going over with prepsol(wax and grease remover) lots of it
then paint it, overlapping each coat, and rememba not to do 1 heavy coat, rather 3 light 1s
then spray your clear coat, if your using 2 pak and a biooth.
then un mask it,
then get some super fine sandpaper, andcarefully rub any runs out, then crack out the buff and away she goes.
jim