Here's some information regarding PCB design. Scroll down to see the class specific FAQ and to get the DRU file.
"One of the key concepts in electronics is the printed circuit board or PCB. It’s so fundamental that people often forget to explain what a PCB is. This tutorial will breakdown what makes up a PCB and some of the common terms used in the PCB world."
Trace? Via? Silkscreen? Gerber? Double-sided PCB? All the answers are on this link.
Sparkfun EAGLE Tutorials
How to Install and Setup EAGLE: https://learn.sparkfun.com/tutorials/how-to-install-and-setup-eagle
Using EAGLE: Schematic https://learn.sparkfun.com/tutorials/using-eagle-schematic
Using EAGLE: Board Layout https://learn.sparkfun.com/tutorials/using-eagle-board-layout
Excellent tutorial if you want to use EAGLE. Note that Sparkfun provide free libs for the products they sell.
PCB Design Basics - EDN
Part 1: http://www.edn.com/design/pc-board/4424239/1/PCB-design-basics
Part 2: http://www.edn.com/design/pc-board/4426878/PCB-Design-Basics--Example-design-flow
Part 3: http://edn.com/design/pc-board/4428665/Component-placement-tips-and-strategies
How to design the perfect PCB
Part 1: http://www.michaelhleonard.com/how-to-design-the-perfect-pcb-part1/
Part 2: http://www.michaelhleonard.com/how-to-design-the-perfect-pcb-part2/
Good overview of the design process, lots of pictures
Altium Designer Tutorial: Schematic capture and PCB layout
Part 1: http://www.youtube.com/watch?v=Y7PY1nBtImk
Part 2: http://www.youtube.com/watch?v=9u0Fzpb0yZU
The Engineer’s Guide To High-Quality PCB Design
EEVBlog on PCB Design for Manufacture
"A how-to guide to taking your electronics project from prototype through to high volume PCB manufacture."
Part 1: http://www.eevblog.com/2010/11/15/eevblog-127-pcb-design-for-manufacture-tutorial/
Part 2: http://www.eevblog.com/2012/01/25/eevblog-239-pcb-design-for-manufacture-part-2/
Ten best practices of PCB design - EDN
Now that I have reviewed some of your schematic and PCBs I can summarize the most common issues.
Feel free to contact me at jfduval (at) mit (dot) edu if you have any questions or comments!