Others have covered the information pretty well. In addition to eating a meal beforehand and avoiding substances I would also suggest drinking lots of water that day. Aftercare for the tattoo is simple. Different artists will tell you different things, but in my experience it's okay to leave the bandage/saran wrap on for two or three hours, then take it off. You may want to wear clothes you don't mind ink bleeding on because the first day it may bleed a little. The first day you'll want to gently wash it with antibacterial soap and warm water. After that apply non-scented lotion twice daily to the tattoo for about ten days. At that point the scab should have flaked all the way off. Don't swim or take a bath following getting a tattoo for at least two weeks.

Good luck! I hope this helps. If you're comfortable sharing I'd love to see pictures, too.