Wet sanding I think I used 1500grit but for knocking down scratches and such I used something heavier. I just bumped the thread I linked to above which has more of a blow-by-blow of the paint job through all the updates. Rustoleum brand has a primer as well I believe, get it and use it. Believe that it makes a difference. There's also been a fair few paint related threads here over the years. Search the Classic and Vintage forum for some of these to get more advice.