If you’ve spent any time whatsoever laying out your own circuit boards we’re sure you’ve run into the issue of not having the best component or package available in the standard libraries. If it’s a common part, chances are the symbol definition will be there. But possibly the footprint you want to use is missing? Here’s an easy to follow tutorial which demonstrates how to assign new packages to existing Eagle PCB components. It even shows the basics of how to tweak the footprint to fit your needs (like making SMD footprints simpler to hand solder).
This will not instruct you how to make your own customized symbols, or how to build packages from scratch. but it will let you locate the package you want to use from a different component, then copy it to your own library for use with different parts. and the techniques shown make this a quick and relatively painless process.
We certainly don’t want to start another comment quagmire like the recent picture v. AVR discussion. but we’ve used both Kicad and Eagle rather extensively and feel that neither one has really mastered part/footprint creation in a user-friendly way. We like Kicad’s total separation of footprints from components, and it’s myriad of parameters which can be used to tweak the layout. but if you use the same components frequently, Eagle’s standard of linking parts and footprints does end up saving a lot of time. What do you think?