Learning the Ropes - The DM as Musician

When I first discovered the OSR, a little more than a year ago, and learned about the concepts of sandbox and players agency, I immediately saw the analogy with improvisational music.

One of the players proposes an idea, using the shared language of the genre, to the rest of the band which, in turn, begins to interact with it, establishing a dialog who can take that idea in many different directions, sometimes very far away from its point of origin.
The improvisational aspect engrained in tabletop RPGs is what attracted me to this wonderful hobby in the first place, and just like when I was learning my instrument, I find myself eager to suck up all the information and advice the OSR godfathers share with the community on a daily basis with the intention of applying it at the table as soon as I have the chance.

And here is where the problem arises.

With improvisational music, there's an important lesson one learns at some point along the path: when performing and expressing your creativity on stage, forget about all the practice you've done. What this means is, spend as many hours as you can shredding in your room, developing all possible chops and techniques, but once you step on stage, play the music, do not practice. Let the muscle memory, acquired during practice, kick in but do not think about it, or you won't be particularly musical in your playing. You conversation with the other musicians won't be very fluid nor will it be particularly enjoyable playing with you.

Now, I found this to be true for DMming as well. I often show up at the table with my brain filled to the brim with a never-ending list of advice I've read on the internet (Jeff Rients tweets alone are enough to fill a book of great DM practices, and in fact they did) and the conscious intention of using them in the game. But in the end, between keeping track of npcs, coming up with stuff on the fly and the general effort of imparting a shred of sense into that mess I just made up, I often fail to apply most, if any, of those tricks and tips I so wanted to make use of.

So I came to the realization that I should probably absorb as much as I can while away from the table and then leave it to my brain's muscle memory to bring that stuff up during play instead of trying to force it. This way I can better respond to what my players throw at me and make the experience flow a lot more.

It'd sure be great to find a way to practice DMming away from the table. Anyone does that? How?