I know you'll get a lot of different responses to your question and here are mine.
1. If you brought it out, you take it back. This mostly applies to garbage. This one really gets me hot. I hate seeing scum bags use the water ways as their personal trashcan.
2. Grab a boating guide people. Use the right of way correctly & drive responsibly.
3. Don't boat drunk.
4. Be respectful of the other folks trying to enjoy the water. It doesn't just belong to you.
5. Help your fellow boaters when they are in distress. For me, this means broke down boats and not when your friend decides to get hammered and picks fights with everyone within earshot.
Like I said, there will be more added to this list.
Brian