Our assumption, at the start of this discussion, is that you are preparing for the SAT exam. In all likelihood, you are considering enrolling for college, and you have been informed that your SAT score is one of the (main) things that will be looked at, in determining whether or not to admit you to college Security+ exam. So, in a bid to improve your SAT scores, and thence increase your chances of gaining admission into the best colleges, you are now proactively preparing for the exam.
The SAT tests a specific skill set: it is up to you to research and find out what that specific skill set it. What we can say, in general terms, is that the SAT exam is all about checking out your critical reasoning capabilities. There are papers for math, comprehension/critical reading as well as writing, but what the examiners are really checking out, through all that, is your ability to think critically in fluid situations. That is the skill you need to build if you are to ace the SAT (and if, by extension, you are to subsequently succeed in college).
Your confidence, as you approach the SAT exam, matters: often, what makes the difference between students who score highly on the SAT and those who basically flunk is not just their innate abilities, but also the confidence with which they approach the exam. So how do you build confidence? Well, one way would be by building the relevant skills and then practicing on past SAT questions, so much that you eventually build in yourself the idea and strong belief that you can easily attain a decent SAT score at any time. If there is somewhere the adage that ‘practice makes perfect’ applies unerringly, it would be in this sort of thing.
Shock on first encountering your SAT exam questions can hurt your score: the way to avoid such shock would be by checking out past (but contemporary) SATs. In doing this, you would be trying to see what format they employ, what questions they involve, what the expected answers (and manner of answering the questions is), and so on. You may even take these past SAT exams in conditions that simulate the real test situation, so that when the time for you to do the real exam comes, it turn out to be something you are completely used to.