Thanks to A Wandering Eyre for pointing me in the direction of Blog about Libraries, who came up with this great list of 20 points on excellent library customer service.

Just to get you started:

1. Get the patrons what they want, how they want it, on time and with a smile.
2. Having a good attitude is not optional: you can’t turn it on for patrons and off for staff.
3. Treat each other well and you will find that treating patrons nicely becomes easier.
4. Follow the Golden Rule, always.
5. Everything you do in front of patrons means something (whether you mean it or not).

Read all 20 at Blog about libraries.