Tip 9: Shortcut to add user to an Organization.
The usual method followed to add user to an Organization is via
Settings link in the top right corner of the projects window -----> People View -----> Add User.
Instead you can click on "New User" on the User Panel in the left side of the project window and add user to an Organization.
Screen shot displaying New User link in User panel:

Screen shot displaying Add New User form: