Oh my gosh, no! Don't check with the books if you're reading for someone! Not professionally and preferably not when you're practicing, either. There are two huge leaps I had to take myself. One was to read without a book and the other was to read in person, also without a book. It just seemed like I could never remember everything I'd learned.
Tarot works on what you see in the cards. If you can't remember everything without a book, then forget the book and just say what first comes to mind when you see a card. Then go ahead through the spread, weaving a story from the cards. If something appears and you can't for the life of you figure out what it's saying, just leave it and come back. If you come back and don't get it, then just move on altogether.
When you read in person, you're not going to do a "this card means this and that card means that" like we do when practicing here. A professional card reading is one where you get paid for saying what you see in the cards as a whole, not so much one card at a time. Put the whole thing together in a cohesive message. Your sitter might ask for clarification on how you see things you've told them, but that's okay. Just tell them what you saw and why.
Even if you're reading for another Tarot reader, the same thing applies. A fellow reader will respect what you find in the cards because they know how it works. They've come to you for your perspective, not for you to show you know rote card meanings.
