Good news and bad news. Good news: The SAT tests 20 different grammar rules, so if you can understand them, you shouldn't get more than a question or two wrong on the entire writing portion of the SAT. Bad news: There's 20 rules, and to do well, you have to have an solid understanding of most of them. The rules are listed below, so go over a block/section per day, and by the test date, you'll have them all under your belt, ready to answer every question correctly!
Note: This method does not work for everyone. If this doesn't work for you, keep practicing and find out what does!
COMMON WORD PAIRS ON SAT: Either/Or, Neither/Nor, Not Only/But Also, Both/And, Between/AND *IT’S NOT OR.*
As/as, (more/less)/than, (so/such)/that, from/to, just as/so.
Things to Remember: 1) Who refers to people 2) That/Which refer to things 3) When refers to time 4) Where refers to places ONLY (Often used as a faulty comparison when talking about things)
Tips for Guessing: Shorter IS better, -ing words are often used INCORRECTLY, PASSIVE VOICE is bad, LOOK TO MAINTAIN MEANING.