For me, it started with a few books.

"Ego is the Enemy" by Ryan Holiday established a great baseline mindset to be in.

"Crucial Conversations: Tools for Talking when the Stakes are High" is the most applicable book. It explains in detail how other people interpret your actions, and how to approach a delicate conversation with care.

Some in person training helps; I quite enjoyed the sessions my company provided from Life Labs.

Mostly you'll learn being a good listener isn't only shutting up and letting them talk, it's also actively considering what they're saying and asking the right questions.

not the op, but the latter applies to me. Absolutely had to experiment a good amount to figure out what worked, and I definitely made errors which were obvious in hindsight well into my late 20s and even early 30s. And something no one ever tells you but is common sense when you hear it: it's impossible for everyone to "like" you (for however you choose to define the word) because no single mode of interaction will build or reinforce a healthy relationship with 100% of people.

Quick tip: movies, dramas, and sitcoms are a terrible reference. So is r/relationship_advice unless you're looking for what not to do.