There is no magic pill.
lamanxa provided you some good links for your specific question. Go over your most recent practice test. Brush up on areas you are slipping up. Fit in one or two more practice tests between now and Saturday and repeat the analysis to ensure you are not repeating mistakes that are killing your score. Don't burn out the day before the test. Feel free to review and go over some material, but make sure you leave time to relax and rest.
Map out your path to the test center. Plan on arriving a little early (15 mins). Pack snacks that can help you through the 4 hour test appt (energy drink, cliff bar, etc. things you know will keep you from getting hungry/thirsty, but not make you uncomfortable).
Best of luck