Your most indispensable "tweak"?

So I picked up a novum pmr premium resonator on the basis of a recommendation in this thread (and other reviews) and the effect it has in my room is beautiful. Hard to describe, but improves tonality, image density, without any negatives. It's also quite beautiful to look at sculptural. I've since found a second one used and am waiting to receive it. Definitely got me more open minded about "tweaks". Love all the ideas here. 

I have to second the Critical Mass footers.
I put a set of 4 of the 1.0 under my Lumin X1 and I am wowed. 
I then ordered 2 more sets for my mono block amps. 

ozzy

I like  sandthemall  basic suggestion. Dedicated 10 gauge wire (shielded) and hospital grade outlets. 

Lotta work for less improvement than a $30 set of Nobsound springs.

redwoodaudio 
Your most indispensable "tweak"?

My 6mtly visit to my ENT Professor to vacuum the old wax out of the ears, after it you swear you come out hearing like a bat.
Scroll down and watch video, and you'll see what I mean.
https://www.insider.com/video-tiny-vacuum-cleans-out-earwax-2017-11

Cheers George