Hi Fritz,
I suggest you Google "judge letter son" without the quotes and look for a letter.
Your format should be something like....
Your name
Address
Date
Your Honor XXX
Position (Judge of whatever court)
Address
Dear Judge XX:
1st Para--Introduce yourself and state your purpose
2nd Para--Provide support for your desire for a lenient sentence...use a few paragraphs if needed.
Last Para--Thank the Judge for his counsel and consideration
Yours truly,
Fritz
Your letter should be short, concise, on-target. The longer it is, the less likely the judge is to read the entire letter carefully. If it were me, I'd try to keep it to 3 pages or less.
If you like, you can read
Martha Stewart's letter to the judge.
Above all, be respectful and polite. Don't blame everyone else. Show contrition for whatever harm you son may have caused.
I hope this helps you.
MountainHiker