Self-Tanner: Whether you use a bottle or visit a spray-on booth, you'll want to make sure the colour is natural. Doing it ahead of time will allow the colour to blend with your skin better.
Facials: I find that facials can cause skin to break out, since some skin types overreact to the extreme cleaning. You want to allow your skin to settle and get back to a normal state.
Waxing: This one is pretty simple! Doing this early will avoid rashes and red welts that are difficult to hide. Give your skin adequate time to heal.
I hope these tips prove to be helpful for you!