Exfoliate your full body carefully the day before. Shave or wax the day before.
Wear or bring dark and loose clothing. Wear no makeup, deodorant, perfume or lotion or make sure to remove due to the session.
Let the liquid applied set for 8 hours then shower with no soap and pat dry. If you sleep before shower, use pyjamas.
AND SOME ADVICE.
No boiling showers or looong sleeps in the ocean, this will shorten your tan.
If your tan gets patchy, scrub it away.
The tan will last about a week.