Shower and lightly exfoliate the area right before your appointment.
Make sure your hair is long enough. for most people, this is 2 weeks of hair growth.
You can get waxed while on your period, just be aware your skin is often more sensitive around the time near your period, and waxing can be more painful than normal.
Moisturizers can interfere with the wax process by not allowing the wax to adhere well to the hair.
Keep hands away from newly waxed areas. Touch as little as possible as touch can encourage irritation or small pimples.
Don't soak for the first 24 hours, as soaking in water could cause unnecessary irritation or pimples.
Don't be around too much heat. Avoid tanning beds, saunas or steam rooms for the next 24 hours.
For Brazilian areas, sexual activity should be avoided for at least 24-48 hours.
Exfoliate. Two full days later, if there isn't any redness, use a mild exfoliator. This helps prevent ingrown hair.