Set the alarm clock the night before
Situational goal adjustment is a real problem.
Don't set the clock when you're tired, set it when you are planning your day. Don't whittle away at your sales goals right after a serious rejection, set them when you're on a roll.
The discipline is in obeying the rule you set when you were in a different mood than you are now. That's what makes it a rule as opposed to a guideline.