Colin Karpfinger who is also the creator of the cool Autonomous Paintball Sentry Gun has made a great article about Ordering your Eagle PCB Designs. Learning Eagle is quirky enough but after your design is done you still need to learn about circuit board manufacturing before you can get them produced. This is because the manufacturer needs specific files that represent the layers involved in making your board. After you make a few it will all start to make sense but the first one can be a challenge. Lucky for us there is a standard that has emerged which is Gerber so once you have used one PCB house to make your boards, trying another should be painless. I think the Gear Clock PCB is the favorite PCB that I have made so far. If you are still hungry for information have a look at the Documentation that our friend Ian Lesnet put together when he was working for HackaDay, and when I was making my first board I used the great guide that Spark Fun put together.
Thanks for sharing your tips with us Colin!