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 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).