Some students come to school with a lot on them. Trauma, life, and just trying to figure out how to grow up. Some days just surviving the day is a victory for them, just like some days it is for adults. Relationship before rigor.
One of the best retention strategies for a school is an administration who takes care of their staff. Not only will they not want to leave, but others will want to work there.
I started every new class by telling them I had heard so many good things about them and I was lucky to have them. Every class, Every year! It makes a difference.