1) Get a good nights sleep beforehand
2) Eat something beforehand
3) Keep yourself hydrated during to help prevent you from passing out
4) Do not drink alcohol within 24hrs beforehand
5) If you are really nervous, bring a friend. ONLY ONE. Anymore will distract the artist and they need to concentrate.
6) If it starts to hurt too much don’t be ashamed to ask for a break. Some shops offer numbing spray too that can help for the more sensitive areas.
7) Know what you want in as much detail as possible. Better yet, bring in reference images if you have any. Last thing you want is to not get what you had in mind. It’s gonna be there forever after all. However, be open to the artist’s suggestions, they do this for a living. And sometimes your ideas need to be tweaked a bit to translate into a tattoo well.
8) Never go into a tattoo appointment with a cover up or removal possibility in the back of your head to ease your nervous mind. If you aren’t 100% sure you want it - don’t get it.
9) Wear clothes to the appointment that are comfy and make the area you want tattooed easily accessible.
10) Lastly, B-R-E-A-T-H-E! Holding your breath will only increase your chances of passing out.
Most of all, relax