Your last week of SAT preparation should be designed for one specific purpose: to increase your confidence.  Having a healthy attitude on test day will dramatically improve your score by focusing all your energy on the things that you can control.  No matter what you know, a wrong attitude distracts you from the task at hand.  To maintain a positive attitude, you can build confidence in your process in a variety of ways:

• Body Rest - Getting enough sleep (8-10 hours per night) for the last 3 days leading up to the test is vital.  Remember that the SAT is designed to wear you down and trick you.  Why put yourself through that when you're tired?
• Mind Rest - STUDYING TOO MUCH WILL STRESS YOU OUT.  Stress will burn you out.  Give yourself plenty of time away from the SAT, especially the night before.  Take it easy and relax.  If you're calm and well-rested during the test, you'll focus harder and for longer.
• Trust Your Process - Effective preparation is a long-term process.  This means that your work is not done overnight but rather a little bit at a time.  Adhering to a sustained routine of practice allows you to stay relaxed on test day; you feel that you've been preparing effectively and know that your best result will come when you're relaxed and ready.

This page contains excerpts from Chapter iii of On Insight.