I know this will invite a deluge of ill-thought out so-called "funny" responses from the usual suspects, but here goes.
I've mentioned elsewhere that twenty seconds per customer at fifteen customers a day is five minutes saved. I have one or two ways I save time, but I'd be keen to hear more.
Before anyone accuses me of living to work, remember that if you could find 12 such tips, you'd have an hour a day more at home with your feet up while still earning the same.
Vin