Hey dood,
You could try this:
1. Clean the surface with mild soap and water (dish soap would be fine) & let it air dry completely.
2. If the surface is flat, you could gloss coat it first with a spray can of gloss. If it is straight plastic it will be fine.
3. Cut the stickers carefully without touching them; use tweezers or hobby knife to lift the sticker using the tip.
4. After placing the sticker use a tissue between your fingers to rub the sticker to smooth it down.
5. Use a gloss coat to seal the sticker by: a. warm up the can in WARM water, b. hold the can about 10cm from the piece, c. start spraying before the piece and pass over the whole thing before you stop spraying.
6. Cover it with an upside-down plastic container to prevent dust etc. from settling on it and let it dry for 24hrs.
7. Wash your hands before working
8. practice on a scrap first
Good luck!
Caseymunchkin