Peel off as much of the sticker as possible by hand
Soak the area with warm, soapy water
Rub the residue with a microfiber cloth
Apply rubbing alcohol to a cloth and wipe the residue
Use white vinegar on a cloth to loosen the adhesive
Apply a small amount of cooking oil or baby oil
Let the oil sit briefly, then wipe clean
Use a plastic scraper or old credit card to lift residue
Try a commercial adhesive remover
Wash the area again after removing the residue
Dry the surface completely
Test any cleaner on a small hidden area first