Many students study for the SAT by taking a full practice test, looking at what they got wrong, and then taking another full test. This is incredibly tiring and not very effective. There is a much better way to study.
The SAT mostly tests a set number of math and reading concepts. Instead of jumping from a geometry question to an algebra question, you will learn much faster if you study one topic at a time. If you struggle with fractions, spend a whole week just doing fraction problems until you master them.
Start by taking one practice test to see where you stand. Look closely at the questions you missed. Group them by category. You will probably find that most of your mistakes come from just three or four specific types of math or grammar rules.
Take those three or four weak areas and focus all your energy on them. Find practice problems that only cover those specific rules. Do them over and over until you feel completely confident. Only after you have mastered those weak areas should you take another full practice test.
Action step: Review your last practice test. Find the three topics that cause you the most trouble. Spend the next week practicing only those three topics.