I struggled with EQ for years until I installed Voxengo's Span frequency spectrum analyzer.
https://www.voxengo.com/product/span/I started EQing my recordings to be "flat", but they still didn't sound that great. So I asked myself, "what do really good recordings look like?"
I've attached an example of Steely Dan's song Aja - It's not flat. (obviously, other musical genres may look different than this...)
So take a look at the frequency response of Handshake Drugs at the 3 min mark. Doesn't look at all like Aja.
I quickly tweaked it with a parametric equalizer (and I recommend that you get a plugin for one). Image attached.
And there's an image of the equalizer curve.
Finally, I attached the "corrected" audio MP3 sample (original from 2-4 minutes). Most of the corrections boost the volume, so of course, this version will sound “better”, but you get the idea.
All of this can be done visually, but from here, you can start to do the critical listening and tweak the kick drum, bass, vocals, snares and cymbals to your liking.
Hope this helps!