Doing well on the SAT means striking a fine balance between speed and precision. If you take the whole test period to get only five problems exactly right, you’ve not done any better than if you’d rushed and essentially guessed on all of them. But if you go too fast, you’ll blow questions that you should have gotten right!
The SAT scoring computers don’t care that you know how to do a problem, but just honked up the process of getting the answer. So you MUST avoid rushing and making careless mistakes. To put it another way, never trade speed for getting right answers. HOWEVER, don’t let yourself hover over a question too long: if you can’t make significant progress on solving it in a few (say 5-10) seconds, mark it in the margin to come back to later, or make an “educated guess” and move on. Making more than one pass through a section is a great way of keeping up your pace while not sacrificing questions that you’re capable of solving.
SAT Prep Plan: SAT Tips 
