Bingo, and bingo!
I agreee that clear, consistant, fair rules need to be communicated with eye contact.
Nothing worked better with my two boys. I would call them by their first name, get their attention, tell them to look at me, I would look them directly in the eye, and let them know exactly...in clear terms, what I wanted them to do or to stop doing, and end with "Do you understand?".
This still works today with my younger 16 year old son.