Bookkeeping for a tattoo shop

I have done bookkeeping for lawyers, retail store, property management etc. but never for a tattoo shop. I offered a friend for free to do the bookkeeping but did not know how hard it would be to learn. Does anyone know of a book, website or actual tattoo bookkeeping program out there? I use Quickbooks rarely for the retail shop my boss owns but am limited in what I know. Any any help would be most appreciated before I pull my hair out! Thank you.