Your most indispensable "tweak"?

Oh, and Stillpoints under my equipment, especially my pre-amp which is custom made but had a dark, slow and mushy sound on it’s hard rubber cone feet. Townsend seismic sink under my VPI TNT turntable-essential due to VPI’s poor vibration control.  My room construction is not a tweak but considered an essential component for music reproduction.  It was expensive, non-defeatable and provides both perfect isolation and bass control.

+1 for High Fidelity.  MI started with the 0.5 and upgraded twice. Not cheap by any means when you start getting into the 1.0 and up, but I just love the clarity it brings. BIG improvement.

A few of my essentials:
Sorcer X4
Novum PMR II
Bybee Quantum Clarifiers

fuzztone recommends Nano Diamant contact oil and I have pondered on the use of this product. - In fact I have ordered some .
As an alternative what about Gallium ? Readily available as a liquid metal thermal paste primarily used for the interface between a CPU and the heatsink in PC's.
Gallium's electrical resistivity is considerably higher than carbon in the form of graphite ,silver or copper but it is a hell of a lot better than air.
Has any member explored this liquid metal?

Always buy the best quality recordings and performances. Most musicians have their ups and downs.  

Using Amazon reviews, I sort newer artists chronologically from first release to last. I read customer ratings, listen to top examples to see if agree, and choose their top rated recording as a first buy. This method rarely disappoints.  

I’m another DeOxit Gold happy customer. Reapply about every 6 months to all component and speaker connections while securely reseating cables.

Mogami Gold studio analog and digital cables are very reasonably priced and won the Best Cable Tweak Award in my music system.