Hi there, I used the TEAS book that the ATI website sells. It was really helpful to me. I thought the easiest part was the English/Reading and the hardest was the Science. But that didn't really correspond with the book tests that I took. Everyone's questions are random, so I guess it's possible to get bad luck and get stuck with some 'harder' ones that you might not know as well as others.. I also took the 2 online practice tests on the ATI website and thought that was the MOST helpful! When is your test? Good luck!
I would definitely say that was super helpful to me (online tests). Just cuz you kinda get the feel for what the real test is like. This was a yr ago but I assume it's still the same- it gives you a real detailed account of your practice test, and answers, and what you need extra focusing on/what to study more of/why you missed what you missed, etc. I'm not in the program yet- on the waitlist right now..