How to make a symbol in Eagle Library

Generally I try to download libraries from CadSoft or Sparkfun

Cadsoft Eagle

http://www.cadsoftusa.com/cgi-bin/download.pl?page=/home/cadsoft/html_public/download.htm.en&dir=eagle/userfiles/libraries

Sparkfun Libraries

old site

http://www.opencircuits.com/SFE_Footprint_Library_Eagle

new site

https://github.com/sparkfun/SparkFun-Eagle-Library

Making From Scratch

If you must create a symbol this is a good tutorial

http://myhome.spu.edu/bolding/EE4211/EagleTutorial4.htm