What you haven't mentioned there is "playing with other people" !?
So by age 21, I had played with loads of different bands and at open mic nights etc. and to me this is what it is all about.
Unless you are aiming strictly to be a solo bassist then a big part of your job is going to be supporting other musicians and there is no substitute for getting out there and doing it as often as possible!
Seriously - nobody is going to hire you as a bass player for your knowledge of theory (teacher maybe?) .
Why they will hire you is if you have a good feel, can play many tunes easily, are easy to get on with and are reliable. Image may come into it - but I never found it a barrier when I was young - what is important is that you can turn up and cut it live.
So my Number 1 priority for learning would be - get out and play with as many people as possible - no matter what the situation!
