Identify the time and lesson
State your name at the time, school or team, approximate year, and the assignment, practice, phrase, or act you remember. Explain one concrete way it shaped a later choice.
Keep the contact appropriate
Use an official, alumni, professional, or publicly offered channel. Do not request private access, share information about other students, or assume they remember every detail.
Let gratitude be the whole purpose
Do not attach a reference, job, money, or introduction request to the same note. If you later need something, ask separately and make refusal easy.