Anyone who promises a perfect result on the ACT, SAT, or LSAT, is probably looking for your money. So, beware! Anxiety can cause all sorts of panic.
Instead, good, old-fashioned planning can cure a lot of the anxiety. Start with the date of the test, and work backwards as to what you will study, what days off, when practice exams, etc.
And treat yourself! When I had to take the Law Boards in a second state because of State Bar regulations, I wasn't very pleased. After all, I'd passed in one state, shouldn't that be enough? I didn't live near the site of the test, therefore I booked into a great hotel, so I just had to walk to the test, and could go back to my room at lunch (the LSAT's last two days). It was a great stress reliever: I actually took a bath before the afternoon session.
So, treat yourself!