I started with trying to make my own custom component (as Id like to start building my own custom library for stuff I commonly use over and over.......one of the biggest downfalls of Eagle for me is searching the damn library for a component that I can never find!)
Here's a little tip that I never realized till the other day. Newark (http://www.newark.com/) is adding Eagle component script files to more and more parts. Just download the script file and run it in Eagle and it generates the part for your library.