The biggest piece of advice I can give you is to read anything and everything. I would particularly recommend articles from sources like Popular Science, the Washington Post, the New York Times, etc. Read carefully, and look for themes, contrasting opinions, author’s purpose, tone, and other characteristics of passages that often appear as question in the CR section. Also, definitely try to build up your vocabulary. The articles will help, but also try to read lots of books, especially ones that are often taught in high school or college as they contain lots of vocab words. I got a 770 in CR when I took the SAT in May, and this is what worked for me. I was a sophomore as well.