Avoid extra costs.
By simply washing the car before you bring it in for wrapping you avoid extra charges from the wrapping company for cleaning the car for you. The vinyl will always go only on cleaned surfaces.
Prepare your car before you wrap it.
For a perfect wrap please make sure you prepare your car by cleaning it, buff it to remove any imperfections on the surface like sap from the trees or road debris. DO NOT WAX the car before you bring the car for wrapping. Just wash the car with soap and water the best you can.
Outgas the paint if the car was re-painted.
If by any chance the car needs to go to a body shop for repairs before it comes to the shop for wrapping please make sure that you keep the car with the freshly painted surface to breath and outgas for at least 2 weeks before you place the vinyl on it. An un-dried paint can cause the vinyl to bubble and also when removed from the car to peel off together with that layer of paint.