While much of music theory and skill can be learned from books, the fact remains that music is an aural — or auditory — art. Like language, whose words and syllables can be scribed upon the page, the characteristics of the music are reserved for the ear alone.
Regardless of your musical ability, there will come a time when you must consciously listen to progress.
Every style of music has its own nuances and idiosyncrasies that cannot be accurately learned from notation. Good examples of this are hornpipes and reels in the Irish music tradition — both are generally notated with straight eighths, but one has a distinctive swing, and the other a very subtle lilt. This is why it is so very important to listen to good musicians. Listening, especially frequent immersion in the genre of your choice, helps you train your ear to pick out the details.
Once you can decipher how things like rhythm, for example, are played in your musical style, you can better determine where your own playing stands in relation.
And once you know where you stand, musically, you can make more accurate adjustments in how you play to better fit within your genre.
So how do you find good musicians to listen to? A cursory Internet search can usually yield a few names to start with. You can also ask around. Most competent musicians are at least familiar with the “big names” in their own genre, and are more than happy to pass along the information. And, don’t forget your local music scene. There are often some completely fabulous Indie artists or music hobbyists who may frequent a local jam session or open mic night that would be willing to answer a few questions.
Good luck and happy listening! 🙂