Don’t try to get the same grades as the girl sitting next to you in Algebra class, and don’t try to get the honor roll like your brother or best friend unless you think it’s a realistic goal. The most important thing is that you do the best that you can do instead of comparing yourself to other people. If you’re too focused on other people then you’ll never be happy with your own achievements and won’t be studying with a positive mindset.
The best thing you can do if you know there’s someone in your class who is more knowledgeable than you is to suggest a study date so you can pick that person’s brain. Think of people with knowledge as assets, not threats.