Here are the College Board's instructions.  Learn them now to save time later.

TERMS TO KNOW

clause (independent/dependent), modifier

WEAPONS OF THE TEST WRITER

Their main tactic is to flood the answer choices with multiple, flawed versions of the sentence.  If you're not looking to solve the specific type of error you spotted in the sentence, sorting through the answer choices can be confusing .

The test writers can only mess up a sentence in a few different ways. For each type of error they can make, there are only a few ways to resolve it.  Knowing this limited group of grammatical errors will allow you to identify and resolve them more quickly on the test.  In addition to the errors types we listed for ISE questions, the test writers often make the following types of errors:

• faulty parellelism

• coordination and subordination

• ambiguous

• misplaced modifiers
  

• run-on sentences

• fragment

To avoid getting overwhelmed by confusing answer choices, you can adapt how you read IS questions and what you write down.

HOW YOU READ

Remembering the common types of errors, read through the sentence and look for the mistake.  Once you've found the error, take a moment to determine what needs to be changed to resolve the error.  Then, with that information in mind, skim the answer choices to determine which one resolves the error properly.

WHAT YOU WRITE

Crossing out incorrect answer choices is one way to keep moving smoothly through the questions.  Developing such a rhythm helps your brain stay active and focused.