Our basic policy is for all teachers to take part in school self-evaluation. For some time, every Thursday after school, we have been conducting a one-hour meeting of all teachers, which I personally call "happy hour". Why? It's not easy to get all teachers to come together to talk about the current situation of the school, and to see what improvements can be made. We use social activities which enable us to break the ice and to more openly review the issues.
It does not add too much to our workload, but on the contrary increase our cooperation and team spirit.