Tipping at the salon

SeeYouNextTuesday • Single atheist badass career Mom. I say it like it is because I'm too old to play games and I don’t have time for fluff. 😘
Do you tip at the salon for basic services? If so how much? 
My hair dresser charges me $35 for a haircut. I routinely give $40. Am I undertipping? 
Also, I'm getting my makeup done at the salon for a photo shoot next month. The charge is $65. I haven't been asked to bring my makeup and don't know if I should. What should I be tipping for this? 
How about for mani/pedi? 
I find these things differ so much from area to area. I don't usually give a percentage at the hair salon, but just round up. Am I handling this all wrong?