I wouldn’t dare defile Douglas Adam’s memory by not mentioning that you should keep a towel with you at all times, but my second contender is a surprisingly short three-parter:
- never lie.
- never tell the whole truth.
- never pass up a chance to use a real bathroom.
Never talk to the police. They are not there to help you.
Anything you say WILL be used against you… It’s hidden right there in the Miranda Rights