How do i get sticker residue off glass properly?

Scrape first, solvent second. Peel off whatever paper is left, then take a plastic scraper or an old bank card to it while it's damp with warm soapy water. What's left after that is just adhesive. A bit of cooking oil or rubbing alcohol on a paper towel, let it sit a couple of minutes, wipe. Glass cleaner at the end to get rid of the oily film. On plain glass a new razor blade held flat is fine too, just keep it wet and never on coated or tinted glass.