the main piece of advice i have for students is this: learn how to fail and persevere. it is a skill that will help you in life far more than perfect grades.
think of failure impersonally. when you fail, you have just eliminated one method that doesn’t work for you, so you need to try a different method in the future. figure out which factors contributed to the undesirable result, and change them. (teachers, advisors, and academic counselors can help you with this if you aren’t sure where to start).
i know from personal experience that fear of failure is often a self-fulfilling prophecy, because it leads to self-sabotage. if you can learn not to think of it as an inherent personal flaw, but rather as a strategy that didn’t work for you and can be changed, you will be well-equipped to face the inevitable failures and rejections that are part of life.