Don't betray a confidence.

Don't fail to show appreciation.

Don't live beyond your income.

Don't be a stingy person.

Don't fail to keep your appointments.

Don't allow anyone to dictate your message.

Don't be lazy.

Don't be professional, artificial, or sensational.

Don't overlook the Bible when looking for texts.

Don't neglect the sick and sorrowing.

And last, but not least: Don't grow old.  "Winter is on my head, but eternal spring is in my heart."  You may die of old age, but you will die young.