Component Standards

Systematic and consistent component selection helps a lot in speeding up the process of coming up with your PCB product. Make sure to have standard sources of component symbols and footprints, regardless of your ECAD software. It is a great idea to use a mixture of your own standardized library for commonly-used parts, and off-the-shelf blueprints for rarely-used parts, as provided by several websites on the internet.

Organized Schematics

An organized schematic with standard graphical parameters is the key for easy transfer and modification of the design. Pay careful attention to designators, sheet templates, the component parameters you would like to see on the sheet, and their font sizes. Connect the components in an organized, yet easy-to-drag and modify way.

Design Rules

As one of my Altium Designer instructors used to say "In PCB, rules rule." Pay careful attention to the different design rules (e.g. width, clearance, vias, etc.) of the PCB before starting the layout. You can either calculate these values or just find rules of thumb for them on the internet or from professionals.

In order to create a layout that works well and is easy to assemble, you need to know what the design rules are for your particular PCB. For example, you should know how wide traces should be and how close they can be to other traces. You should also know if there are any special rules regarding vias or other connections between layers of your board..

Initial Placement

When you're designing a circuit board, you need to consider how the components will fit together. You can make an initial placement of the components and get an approximation of the board size, ways of traces, and how many layers you'll need. You can also export an approximate 3D file to your mechanical teammate before finishing the layout.

Coordinating Fabrication Requirements

If your board has relatively special requirements for fabrication, such as not being an FR4, not being 1.6mm, or being designed for use in a high temperature environment, it is better to coordinate with your PCB supplier about such details and what can they offer and advise.

Special PCB Considerations

There are special considerations for multilayer PCBs, high-speed design, and RF designs. Each of these categories have their special considerations. For example, you may often want to make excellent power planes (or polygons) for power boards, and ensure good return paths for transients.

Routing Priorities

Always start with the most critical nets (connections), those nets that have special considerations for routing compared to others. For example, if you are working on an MCU circuit, start with the clock and communication lines before IO, and so on. Try to choose the shortest, most straight-forward path for any net (unless you are making a PCB antenna or an intentional loop), without much turns, loops, and layer transitions, even if it was a low-speed net. Avoid right angles at all costs, unless it is a power line.

Proper Coupling

Sometimes you have to include two or more coupling elements for a pair of nets. For example, you may want to put two coupling capacitors between VDD and GND, one that is very close to the MCU (which is called local coupling), and another far one near the supply contacts.

Clearance and Creepage Rules

Sometimes you have to be even more careful than the DRC; ensure enough distance between high frequency and high voltage layout elements, and other elements. This way the hazards of noise and transients are greatly reduced. In most cases of high voltages, creepage should be considered as well.