Did you know the UN has a site dedicated to peacemaking?

They also have a mediation response team always on standby ready and able to help when called upon.  

From the site:

STANDBY TEAM

Established in 2008, the Standby Team is a group of full-time mediation experts that can be rapidly deployed to provide technical advice to United Nation’s officials and others leading mediation and conflict prevention efforts. Team members possess expertise in a wide range of issues that tend to arise in negotiations including constitution-making, gender issues, natural resources, power-sharing, process design and security arrangements.

Read more about the team and more on the UN and peacemaking [HERE].

Read about "Guidance For Effective Mediation" [HERE].