Not letting people disturb your own peace.
It’s easy to get caught up in others problems (especially at school) but it’s good to draw a line of boundaries and take in mind that your own well being and mental state is important. Making sure you take care of yourself both physically and mentally will help uplift your own peace too.
Something important to add could be avoiding drama and conflict you don’t need to be involved in, someone else’s stress will just add onto your own stress.