Short sweet and to the point.
How should I write a club resgination letterHow do I write a letter to resign from a club?
You'll need to include your personal information - name, club number, or any other info that is used to identify you.
If you are resigning due to an issue you are having with the particular club, it's good etiquette to explain that - politely - in your letter. This will help the club improve upon their policies. If your reasons are personal, you need not explain, but it's a nice gesture to leave on a kind note ... let them know that you've enjoyed your membership, but you simply can't continue with it at this time.
Whatever your reason for leaving, try to keep your letter congenial and pleasant, regardless of how upset you *may* be ... it speaks highly of your character.