Project Lessons Learned
One of the greatest contributions of a PM to an organization is the set of lessons learned.
After every project concludes, a formal meeting with all of the team members should be conducted and both good and bad experiences should be duly written down in a document that should be a part of the project.
But it does not end there. There should be a kind of library of lessons learned from each project implemented in the organization, to save time and effort and implement best practices born from within the organization.