Use compact loops for dv/dt and di/dt circuit paths (power loops and gate
drives).
Use minimal, yet thermally adequate, copper areas for heat sinking of
components tied to switching nodes (minimize exposed radiating surface). Hide
copper associated with switching nodes under shielded magnetics, where
possible.
Use copper ground planes (possible stitching) and top-layer copper floods
(surround circuitry with ground floods).
Use a 4-layer PCB, if economically feasible (for better grounding).
Minimize the amount of copper area associated with input traces (to minimize
radiated pickup).
Heat sink the quiet side of components instead of the switching side, where
possible (like the output side of inductor).
Use Bob Smith terminations, Bob Smith EFT capacitor, and Bob Smith plane. Use
Bob Smith plane as a ground shield on input side of PCB (creating a phantom or
literal earth ground).
Use the LC filter at DC-to-DC input.
Dampen high-frequency ringing on all switching nodes, if present (allow for
possible snubbers).
Control rise times with gate-drive resistors and possibly snubbers.
Switching frequency considerations.
Use of EMI bridge capacitor across isolation boundary (isolated
topologies).
Observe the polarity dot on inductors (embed noisy end).
Use of ferrite beads on input (allow for possible use of beads or 0-Ω
resistors).
Maintain physical separation between input-related circuitry and power
circuitry (use ferrite beads as boundary line).
Balance efficiency versus acceptable noise margin.
Possible use of common-mode inductors.
Possible use of integrated RJ-45 jacks (shielded with internal transformer and
Bob Smith terminations).