How can we build a culture of trust and support that encourages teachers to observe each other? Some models include "for stakes" peer observation, some include non-evaluative feedback. I think the latter is more practical initially if we are building a system from scratch. The goal is to empower teachers to create cycles of continuous improvement.
I envision a system where a focus is identified by a team of teacher leader in conjunction with the administration (i.e. How frequently/effectively do we ask questions to check for understanding?). The admin secures coverage for classrooms so that teachers can complete initial peer observations to gather data. The teacher leaders and discuss their findings together, then present them to the larger staff. The staff is invited to analyze/brainstorm next steps. Admin/teacher leaders can provide resources to support teacher skill development.
Several weeks later, a second round of observations are completed and similar data is gathered to determine if progress has been made. Similar data gathered, analyzed, reported out to staff. This "cycle of continuous improvement" can repeat as often as needed, for potentially many topics (How to improve dismissal procedures, How to improve parent attendance at evening events, etc.).
The key is leadership that empowers teachers to drive the work, guiding them toward appropriate goals, but having enough trust and confidence to release control such that teachers drive of the projects.