Mercedes,
I believe that you hit on the most important retention technique and that is communication. If we communicate with our employees so they know what is going on, they know what the goals are, they know why, they will be more likely to buy into what we are trying to do and will engage in activities to accomplish those goals together. So often supervisors will not share information because to them information is power. That usually backfires. Sharing information empowers people.
The other "retention technique" is to treat everyone with dignity and respect. If people are treated well, they will return that respect and ultimately, it is the students who benefit. Integrity, as you said, becomes a part of that too.