In some ways, the idea of resonance is the most critical thing in choosing a martial arts school. In some ways, it’s the worst one.
I stole the term from Dan John.
I'd strongly suggest that you take some time to look at a bunch of
different training programs to see which ones "resonate" with you. When I
read the workout of the Iranian Superheavy, something in my core says,
"Yes, that sounds right." When I read about the 1000 crunches a fitness
model does before her one hour of cardio, my brain looks for potato
chips. - Philosophy of Physical Capital
Dan is talking about strength training, but the same idea will apply to martial arts. If you are poking around, either in books, online or in person, pay attention to the things make you say "yeah, that sounds right." Pay equal attention to the things that strike you as stupid. One way I can identify things that don't resonate is I stop watching videos of them. If I have time, I'll watch a whole Muay Thai match, sometimes several times. I cannot watch more than about thirty seconds of Tae Kwon Do. Sorry TKD guys...I just can't. Brain starts looking for potato chips.
The problem with resonance is that it's subjective. I can't tell you what resonates with you, because it's all about personality. I have a friend who prefers kung fu to karate--no rationale reason why, he just does.
If an art draws you in, follow that path.
How do you know if something resonates? If you keep looking at videos of it, it might. If you find yourself intrigued, and wanting to learn more, that's a good sign. Sometimes, it's just an emotional vibe. Judo creates a vibe in me that BJJ does not. I like BJJ...but I LOVE Judo. There's no reason for it, it just is.
A couple of words of caution on this.
1. It is easy to rationalize your resonances. Some people will try to make theoretical arguments to support why their style is the best. These are almost always emotional and have little to do with the facts. Resonance doesn't have to be rationale. If you like something, just go do it, and don't worry about rationalizing why it's awesome.
2. There is a difference between finding an art that resonates with you, and being drawn in by a charlatan. There are bad guys in the martial arts, and some of them are very charming. Do not mistake charm and guile for resonance. They are not the same. (More on this later)