The sticker residue will come off with Goop-Off or similar.
Magic Eraser will help with many types of marks on the metal part of the case (and elsewhere) where bare metal is NOT showing through. NOTE: do NOT use on the inside dark gray part of the bezel - that's usually just painted on (i.e. not solid colored plastic all the way through) and can rub off.
You have metal showing through on some parts of the case, so there's nothing that can be done there besides painting (which you can try, but you'll never match perfectly, so most people repaint the entire thing).
Chipped plastic would have to be filled (bondo-like is usually best), then repainted... I would honestly not worry about it.