How do you do knowledge sharing in a Project?

This should take place during all of the project stages. You need to share knowledge between the customer, management, & your subject matter experts during the study phase to ensure that you conclude to a clear common understanding of the project charter. You need to share knowledge between the project manager, project team members, customer rep., & management during the planning phase. Effective knowledge sharing also important between project team memebrs and cusomter rep during the project execution phase.

I found that the best approach is to integrate an effective communication plan into the project plan and ensure that feedback is received to proceed.

Involve the team in preparation of the WBS and Project Management Plan. This will enable them to have a deep knowledge of the project and will also give them a sence of involvement, motivation and team buy-in.  

E-mails, stakeholder meetings, reports etc.

The important thing is to know that there should not be a information overload i.e. Only interested or directly affected members should be notified of any changes or updates.