2000 grit wet sandpaper, trigger spray bottle with clean water. One panel at a time using tri-fold sandpaper and an open hand thoroughly sanding lightly until the entire surface has been sanded. Rotate sandpaper and keep the surface and paper clean throughout the process. Follow up with a good compound using an orbital polisher and proper polishing pads. Stay away from your edges. This is the short version. I would recommend visiting your local detail supplier for products, tips and further guidance. Ask lots of questions and don’t proceed until / unless you are comfortable with the process. I would also recommend you do a trial run on an old used body panel to perfect your technique before you attempt the process on the Avanti.