This is the second and final article of the Eagle Tips from allaboutcircuits.com:
Before searching on the internet for new libraries to add to Eagle, first make sure that your device does not already exist in your local libraries. To check, use a search pattern that includes ‘*’.
For example, if you want to add a 7805 5v regulator, you must search for *7805* instead of 7805. This will search for any part with 7805 in the middle of the name, without regard for the beginning or end of the part name.
Eagle CAD Tips and Tricks Part 2 – [Link]