When you've done enough practice tests, you sorta form your own way of answering questions, and developing a "gut" answer that is weirdly correct almost everytime.
I'll share one of mine : for sentence improvements - answers with some form of "being" are usually wrong, because of awkward structure
all you uber-i-know-everything-there-is-to-know-about-the-SAT
please add to the list! I need all the help I can get