[Your letterhead, if desired; if not, your return address]
[Date of letter—month, day, and year]
[Recipient's first and last names]
[Street or P.O. box address]
[City, State ZIP code]
Dear [recipient's name]:
I am writing to let you know how sorry I am for drinking too much alcohol at the party you had at your house over the weekend. I know my behavior was inappropriate and that I said some things that I now regret. Acting this way is definitely not how I usually behave or operate. Please also convey my apology to your family and friends.
Is there any way that I can make amends for this error? I really want to do something that could at least partly make up for acting the way I did. Maybe I could help you with your landscaping project that you mentioned at the party. Just let me know, and again, I am sending my very sincere apology for my behavior.
[Sender's first and last names]