Basic 33 RPM LP Cover / Jacket Repair From Ebay™, of all places.
It's part of their new "Reviews and Guides " feature.
Most of the other tips fall into the "everybody else is lying except me" category, but this guide has some useful techniques.
I don't agree with the section on taping up imperfections though.
It encourages things like people using masking or electrical tape to fix splits and tears; as was the case with an otherwise gorgeous Calypso-Limbo record I found that was delineated with some kind of brown cloth electrical tape whether it needed it or not.
I bought it anyway, but still...........
See Also: The Nickety Split Method to Repair Record Album Jackets