Clearly state your request or indicate what needs to be done and give as much detail as necessary for the task, project, or other assignment to be accomplished. If a problem needs to be resolved, clearly indicate what the problem is and, if desired, how you would like it to be solved.
Give the reason for the directive, if desired.
Specifically state how you expect the reader to proceed in order to accomplish the task.
Give the deadline for which the task or project should be completed. Arrange for follow-up or evaluation if needed.
Mention the benefits of the directive to the people involved, if applicable.
You might include the names of individuals the reader could contact or identify available resources that can help him/her to complete the project or other assignment.
If appropriate, offer to give assistance if needed or offer to answer any questions or address any concerns or problems that arise.
Thank the reader and close by expressing your confidence that he/she can complete the task at hand.