Which production concepts/techniques have improved your production the most?

[enroe]

I see it being more around giving the main parts enough space to carry a theme,
and also allow notes to ring out and hold, letting a theme hang there,
before continuing.

This is - in my experience - the crucial thought.

[djdonuts617]

MetricAB for reference tracks

[Gordonjcp]

Don't know about a second but there is tons of music with silence in it.

Such as?

Your old pub rock classic "false ending". See "Strange Brew" by Cream for a good example.

[3lu5iv3]

Can't believe nobody has said sidechain compression yet. Gamechanger!

[3lu5iv3]

Can't believe nobody has said sidechain compression yet. Gamechanger!

probably cuz it's a mixing technique.

[enroe]

Actually, that's the crucial question: Which method has advanced
song production the most—or even advanced it at all?

After several years of production and some experience – with all
sorts of individual techniques and tricks – my conclusion is this:

Taking a break and listening to the song after a while with fresh
ears is the most important thing. This is when you really notice
what needs to be changed and improved. You can hear how the
song affects new listeners—and what definitely needs improvement.

The problem is the habituation effect: You work on a track or song
for a long time and get used to everything: the melody, the rhythm,
the overall sound, etc. And in the process, you lose the ability to
evaluate the song at all.

That's why long breaks, a long time gap and listening with fresh
ears are the most important thing of all.