Try to understand your peer’s perspective and appreciate that they are different from you. Maybe they’re having a hard time with a subject you always found easy. Try to recall a time you were struggling with something. Treat them like you would have liked to be treated in that situation!
You don’t ever have to know everything! If your peer asks a question you are unsure about, tell them that you’re not 100% sure. You can look it up together, ask fellow tutors, or check your old notes and get back to them later!