Many variables to deal with. I presume that your paint job is not new and thus cured. In order for the new paint to bond you must have a clean surface. Best to clean the surface with polishing or rubbing compound. This will take off the wax. Wet sand the surface with 400 grit. Mask before sanding so you don't scratch what won't be painted. Even if you do, scratches can be worked out with 1000 to 1600 grit wet sanding and polishing compound. When the stripe area is clean and satiny, wash it all down with detergent. Now re-apply your stripe masking. Use the good masking tape from your local paint store. It costs a little more but it's well worth it. Consult with your paint store. They can keep you straight on compatibility issues (laquer, urethane, acrylic enamel, whatever). You may not even need a primer if your base paint isn't rubbed through, presuming your stripe is dark over a lighter paint. If you use a primer, use a color similar to your stripe. A good compressor and hvlp gun are nice to have but if you don't, and you don't forsee the need for one in the future, you can do a very decent job with spray cans of good quality automotive paint. Again, consult your local automotive paint store. They've seen it all and are usually quite helpful. After your paint is applied and safely set up, unmask the stripe and have a good grin. I find that the hardest part of a paint jop is waiting for the paint to be dry enough to remove the masking. It's like Christmas and I'm seven again. The final cleanup is the edges of the stripe. You may have a raised, sharp edge where the paint abutted the masking tape. You can shave this edge, carefully of course, with a sharp knife or use the super-fine sandpaper and polish it out with rubbing and polishing compound. One problem using primer is that you may have a fine primer line showing between the stripe and body paint. Do not despair. The cure makes an even classier stripe. While you were in the paint shop, snooping around, you probably noticed packages of striping tape of different colors, widths and multiple stripe tapes. You can match your stripe or contrast/compliment your color scheme. Consider a double stripe. It will give you body/tape/stripe/tape/stripe combination to really sharpen the impact of your work. Probably the trickiest part of any of this is making a straight line with tape. Start with reference marks (light pencil, don't engrave the surface). anchor the tape firmly at your starting point. Then roll off enough for all of this panel. Sighting down the tape, pull it firmly but don't stretch it. As you lower the tape to the surface, it will make contact and barely stick. If it's not quite where you want it, lift it up and try again. This way you can ease into body contours and put the line where you want it. When you have it where you want it, press the tape down and especially at the paint edge, rub it down with a cloth. You can now mask the rest of the body ( I use newspaper ), taping it to your stripe edge. One other note on striping tape. After you've got your tape in place. rub it in thoroughly with a cloth so that the adhesive bonds to your paint. When cured, it is bonded like paint. For the multiple stripe tape, it has a clear mylar tape on the top side which holds the stripes in correct relative position. Peel off the paper that protects the adhesive at the bottom of the tape. Apply the tape. Rub it in good. Now peel off the mylar top tape. Rub in the stripes thoroughly. Most important of all, have fun with it.