As this article suggests, the are really no good reasons for Juniors taking the SAT’s early in the 11th grade year. That is what the PSAT is for. Or the ACT equivalent. Pretty obvious. The real issue is making sure to take the PSAT in the Fall as a junior and then use the results intelligently to prepare for the SAT in the Spring rather than taking the test book and answer sheet and stuffing it in the drawer and forgetting about it.
Because the PSAT/SAT testing progression is a painful experience, it is easy for students to want to avoid thinking about them. What students need to do it attack the monster and take it down one step at a time. First, figure out why you got the questions wrong that you did on the PSAT. In the math part, this is fairly easy to do. With the reading section, it is either usually a vocabulary problem, or the answers just not being the best answer, rather than an answer that is partially right and partially wrong. Again, spend time analyzing why you got the questions wrong.
The Writing section is basically usage and grammar. I am not a big fan of this part of the test and most colleges do not assign the same weight to it as the other two parts. But, check with some colleges that you might be interested in attending and see what they say about how they treat the writing section.
Then, take the practice SAT that College Board provides to high school Guidance Departments under timed and test conditions. It is free but it take discipline to do this. But first, work through every single prep problem in the front of this booklet. Then, take the test and see if you make the same mistakes twice. There is not much you can do about vocab from the time you get your PSAT Score Report back in December and take the SAT in March, but it is possible to think through how to decipher the meaning of words through brushing up on prefixes, root, and suffixes of words.
Also, know the structure of the test and how long you should plan to spend on each question before you cut your losses and move on. It is critical to remember that you just won’t be able to get some questions right and best to have an intentional strategy of knowing when you cross that threshold.