The American Management Association asserts that employees eager to advance their careers should seek options for training that will polish their skills and increase their knowledge. A letter to your supervisor will show the correlation between the additional training you seek and your job's objectives.
Explain how the requested training will directly benefit your department. Training allows projects and objectives to be approached with more confidence and professionalism, increasing your value to the company. This, in turn, increases your company's standing and level of expertise within your given industry.
Provide in-depth detail about the training curriculum, noting that you could not acquire this knowledge in your day-to-day activities. List the sessions you will be taking. If the person conducting the course or seminar is well known, highlight this, along with her accolades or achievements within your industry.
List all costs for your training so your supervisor can budget accordingly. In addition to registration fees and tuition, make sure you include costs for travel, meals and accommodations if the training is outside of your city.