The way I did it is peel off the tape after a good 1st coat while it's wet, right after your done spraying and put the can on the ground then peel that bad boy off fast. Then tape 2 pieces of tape together just enough to where both have half of the sticky part showing on both sides (sorta like double sided tape but half is not sticky). Then place the tape, the bottom half should be sticky side facing you so it won't adhere to the plasti-dip on the car and peel off with the tape. Place the tape right on the now dried line so you can add more paint on your edge so its thicker. and just repeat that process so you can build up the edges layer. It takes more work but is worth it for nice lines and thickness.
Tried to make this as visual as possible so hopefully it helps.
Oxford White Roush Stage 1 SN# 6925--SOLD but never forgotten!
Kona Blue GT premium - Slammed on BC's and BMR's full rear suspension