Not too long, not too short. A happy medium of hair length is about a 1/4 of an inch. Picture the length of your pinky nailbed. If you have shaved, please allow atleast 2 weeks of growth.
A warm shower and gentle exfoliation is recommended before your appointment. A thorough wipe if you're on the go. Avoid lotions or oils, as it may interfere with the hair removal.
For the first 24-48 hours, avoid direct heat and/or sunlight to the freshly waxed area. This may include a hot shower or bath, tanning or intense exercise.
Exfoliation is key! This will keep the skin from bumps or ingrowns. Loofah gloves, a dry brush or products with salicylic acid, benzoyle peroxide are a few recommendations for maintenance in between wax appointments.