Ask the engineer if there are any points that need to be guarded, and how to drive the guards. Ground planes have a similar shunting effect on capacitively coupled noise. They are most effective if placed directly between the source and the sensitive node. Separate sheets of metal have the same effect, and also will block radio waves and high frequency magnetic fields. Magnetic fields are hard to shield below about 10 kHz.
Shields are most effective when they completely enclose the sensitive circuit.
Wires can carry noise in and out of a system, but adding the right filters will stop it. Placing an impedance in series with the wire will reduce the noise current, and adding a capacitor to ground will keep that current from producing a large voltage. Even the power supply lines often need small series impedances. Small resistors, ferrite beads, and coils are all suitable in some cases. Many EMI filters are available off the shelf.