Becoming a "good bassist" is a relative and moving target. When I started, good was just about anyone that could hit the fundamental on time and with some feeling. Quickly, moved past that. I got to know the diatonic scale, pentatonic scale, the chords for each note in each scale, and then modified scales. After, some time knowing these and how to move around the fretboard, it wasn't good enough. Then came focusing on eliminating all extra noise, buzz, and more on dynamics. Still not there! Using digital recording was great, but forced me to really think about timing, ahead of the beat, behind, dead on. I think focusing on each of these things would be easy in hind sight, but learning and "hearing" each takes time. You can make significant progress in just a couple years, but never attain "good". The encouraging thing is, you probably are better than you may perceive yourself. Its a journey, not a destination.