'When it's a Friday don't get excited' - your advice for starting school
15 August 2017 Last updated at 06:59 BST
If you're about to start secondary school or you've already been through it, you'll know it's a big change.
You might feel lots of emotions, like being excited, nervous, worried or even scared.
Newsround have spoken to children who have just been through their first year of high school, to get their advice.