what did you wish you knew before your first tattoo?

i’m getting my first tattoos on friday for my 18th birthday. i’m getting a 7x7cm black and white tattoo on both of my thighs, and then another 7x7 either on my inner upper arm or the side of my chest/ribs. i know the last one is going to be way more painful but i have a high pain tolerance and i’m prepared for it. what are some things you wish you knew before getting a tattoo, like what to do before the appointment, aftercare and healing etc (other than the basics)