With the body lines taped I blocked sanded the top 1/3 and bottom 1/3 of the sides with 320 grit sand paper. Then using the 1st tape line as a guide, I ran tape above or below the first tape line so I could block sand the center section of the car. This creates straight but sharp body lines that need softened. After removing all the tape I went back over both sides with 400 grit sand paper softening the body lines.
600 grit paper is next one step away from sealer :-)
Thanks
Pat