The level of how “good” you are is defined by your competition.
For example, if you are playing with neighbors once a week around a home table, a little extra self-improvement effort makes you the big frog.
In a pool hall, the regulars are of higher caliber. It will take a lot more time and effort to improve enough to become competitive—and a lot of practicing (and instruction) to rise to the top of that group.
There are three things that determine good:
Breadth of knowledge
Knowledge is gained from experience (this assumes you are paying attention to your mistakes—and the mistakes of others). You learn the most from losing, and the least from winning. To gain knowledge, when you experience a loss figure out what the causes were and practice the skills needed. Make mental adjustments to your playing style. That is what will improve your chances of success.
Whether we like it or not, failure is what sharpens the mind. Keep in mind that nothing can be learned from success, except that you become a little too arrogant and there are a lot of people who will be happy to trim your pride.