Feedback and Supervision

Clarity - - Be clear about what you want to say.
Emphasize the positive - - After all, you are taking the time to work with your employee in an effort to help them better understand and better meet your needs. They obviously have promise, and you would otherwise like to continue working with them, so start off by letting them know what IS working, and the qualities in them that you like.
Be specific - - Avoid general comments and clarify pronouns such as “it,” “that,” etc.
Focus on behavior rather than the person.
Refer to behavior that can be changed.
Be descriptive rather than evaluative.
Own the feedback - - Use ‘I’ statements.
Generalizations - - Be mindful of words like “all,” “never,” and “always.” Try to be more specific when giving employment feedback - - concrete examples and specific incidents are far more helpful in identifying problem areas.
Be very careful with advice or getting hung-up on unimportant details.- - People rarely struggle with a task or an issue because of the lack of some specific piece of information. Usually, the best feedback helps the person to understand why the issue is important to you, how you want the task done, and what needs to be done - - by both parties - - to accomplish the task or address the issue.

From: McGill and Beatty (in "Action learning: A practitioner’s guide", London: Kogan Page, 1994, p. 159-163)

Why Should You Supervise Your Employee?

Well, because good supervision benefits both the employer and the employee.

Supervision geared toward helping your employee gain competency makes them feel supported and valued, and makes the relationship more productive and beneficial.
Supervision can explain the requirements and responsibilities of your employee, how you would like the work to be done, and the details that you think are important, so that expectations are clear from the beginning. This can prevent problems later, and if they do arise, provide a standard against which performance, behavior, and relationship can be measured.
Poor performance by an employee that goes unaddressed, can serve to reinforce the poor performance, or even be considered tacit acceptance and approval of the work being done. Proper supervision can catch poor performance, behavior, or attitude early by identifying areas of concern and working on them together.
Adequate supervision can also help to recognize and address potential problems before they become actual problems.
Good supervision functions to help keep good employees. It lets them know that you care whether or not they do a good job, and that you are willing to work constructively with them to resolve any problems, should they arise. These are factors that keep people happy with their jobs, and encourage them to stay.
Good employment supervision models the type of relationship that should exist between people under any circumstance and in any situation. Employers that understand this idea treat all employees with respect, focus on the professional and personal needs of the individual employee, and inspire enthusiasm for the work and loyalty to the employer.
Supervision, coupled with constructive feedback, can result in better employees who feel they are a more fully appreciated and valued. Again, the end result of this is a stronger and more mutually satisfying employer-employee relationship.