"Everything I know about doing reference I learned on the job."

From NexGen Librarian:

For all of you new reference librarians just starting out on the job, here's something I recommend: ask your new supervisor to take you up and down every aisle of the reference stacks and show you his/her favorite reference books. These books will curb your overreliance on Google, and give you further ammunition against those who would say 'if it's not on the Internet, it must not exist!'

If your supervisor is a seasoned librarian, particularly the kind who loves doing reference, this request will impress. This will also get you in the know about any localized resources - tax maps, county documents, evacuation plans - that you wouldn't have otherwise known about, especially if you aren't from the area.

Then, take it a step further: every day, pull 5 reference books you've never seen before, spend about half an hour looking them over and making notes about their scope and what kinds of information requests they might be good for. Keep a log, and organize it by Dewey number. This is how I found hidden gems like a book on how to pose taxidermied animals so that they looked natural, a book of old treasure maps from the Library of Congress, and instructions on how to construct a hamburger-shaped bed, complete with pickle pillows.

Not that anyone ever ended up needing these things, but if they had, I'd have known where to go!