Hi Steve, how about these 2:
1) The cleanest, lowest impedence and most stable electrical supply you can manage.
2) Considered steps to keep external vibration away from your system components.
Practically, this means a number of cost effective steps, listed in ascending levels of nerdiness below:
First, a dedicated radial mains supply with oversized conductors (this one gives the best benefit/cost ratio of all tweaks that I have come across)
An oversized balanced power supply (BPS) for those who suffer from dirty mains
A solidly mounted, light and stuff wall shelf for turntables.
Separate sensitive "brain" electronics into a different stack from the "brawn" components that contain mains transformers.
Keep switched mode power supplies away from your Naim electronics.
Keep your Naim Burndy cables and interconnect cables away from each other, all walls and floors (apart from the pre to pre power supply cables, which should stay together)
Disconnect and reconnect all electrical cables every few months to clean the contacts.
Shut down the system and restart it every couple of months. It seems to rejuvenate the power supplies, somehow...
Finally, do wiggle your Burnby cables from time to time. It's an embarrassing, inexplicable practice for those with true OCD, yet mysteriously effective!
There are many more (cue DB the master here!) but this is a starter for 10 to get you started.
Best regards, FT