Here’s an article from Analog Devices going into the details of high-speed PCB layout design. While the article mainly focuses on analog electronics, lots of good tips can be picked up for digital designers as well.
Intelligent circuit-board layout is important to successful op-amp circuit design, especially for high-speed circuits. A good schematic is the foundation for a good layout; and close coordination between the circuit designer and the layout designer is essential, especially in regard to the location of parts and wiring. Topics to consider include power-supply bypassing, minimizing parasitics, use of ground planes, the effects of op-amp packaging, and methods of routing and shielding.