Remove any unwanted hair a couple of days before your spray tan session. This is especially important if you tend to wax your legs and underarms because it gives time for your open pores to close up. If fake tan is applied immediately after a wax it can lead to a spotty finish and possible streaks.
It's a good idea to exfoliate your sink the day before your spray tan to remove any dry or flaky skin. Also moisturise your skin for a few days before the spray tan session to ensure the top layers of skin are well hydrated
But DO NOT put moisturier on your skin on the day of the spray tan, as some moisturisers can affect the spray tan.
Allow time to get to your appointment, because if you arrive hot and sweaty then potentionally this could cause the spray tan to be patchy.
Also make sure you are fully dry before getting dressed again after the spray tan session.