The title should be a clear description in a couple of words what did you do and why did you do it.
To further ease our work you could add a tag in front of the title. For example [FIX] or [ADDITION], but you may create your own if you so desire
The description is for further clarification of the additions or fixes.
One of the reviewers must always be the leader of the team Tsvetelin and you may assign as many as you want but not too much. You can assign anyone to the pull request but it's a good idea to be one of the team. The pull request should be properly labeled and if it accomplishes/helps accomplish a project goal it should also be noted. Also if it is a response to an issue it should be noted as well by linking it.