1. Read! Books are an escape and an entry to someones mind. The more you read the easier is it to express yourself properly.
2. Although having good grades and being eager is a good attribute, don´t forget to have fun and care for your social life. The world is better with true friends. Don´t be anxious about the future and don´t stress if you could´t accomplish your goal - be brave about the future.
3. Friends are great. It´s not the more the better. It´s nice to know a lot of kindly people but always stay in contact with your closest friends. Grow up together, share your experience, don´t fight over insignificantly things. Sometimes peace is more important than being right.
4. Try to motivate other students. It´s okay to be sassy. Be confident with your own results but don´t brag about your success.
5. Just Hermione… (know your learning content)
Sources: 1 / 2 / 3 / 4 / 5