There are two ways to improve your service, and yourself: maximize your strengths and minimize your weaknesses.
The bottom line is a by-product of taking care of your main product - your customers.
If they're going to remember the problem, make sure they remember it fondly.
Promise too much and you'll have plenty of room to fail. Promise little and you'll have plenty of room to excel.
Your promise means more than the words you use to give it.
Developing great employees attracts great customers.