that was just a real quickie explanation.. if ya tackle it, Jerry and I can give ya detailed stuff i'm sure..
as Jerry said, make sure you get them all the way out. and really, in the bodyshop, you would put a little primer over the area to seal up any featheredges, etc... if its in the middle of the roof or hood it can be a difficult blend, most times they'll spot in the color, dust it out for a blend and clear the whole panel.. but you can blend clear in the middle of a panel, but you usually like to keep it to a minimum. much easier down on a door where you have bodylines, etc to kill it with a backtape or such...
if priming, wetsand with 220/240, prime, 400 wet on primer for basecoat. if ya wanna try and get away without prime, go right with the 400...