I've never done it and now I wont have to for awhile no stripes but have heard that you can use masking tape to help prelocate/mark position. I'd say wipe down the application areas with wax and grease remover. Spray a solution of water and a tiny bit of dish soap then carefully squeegee out the water and let dry.

Some folks say the sun and a pin (ouch) can take care of bubbles? google it