I had been playing for about 14 years, had been to Berklee when I moved to NYC in 1987 and realized that I had run into a brick wall - the players who really spoke to me had something going on that I just didn't know how to get to. They weren't just playing a bunch of notes that "worked" with the chords, their playing had direction and intent, it had meaning. So I took some lessons with a couple of well known jazz players and it was still "Here's some vocabulary to play when you see these chords", nobody talked about how to imbue your playing with any kind of direction or meaning. Then in about 95, someone handed me this article
, and I started studying with the author and, as Frost said, that has made all the difference. I was able to stop playing gibberish and start making sense.
A good teacher will have a well thought out pedagogical approach to teaching you the skill sets you need in a flexible enough fashion to accommodate how YOU learn. There are 3 areas, to my way of thinking, that must be addressed:
1. TECHNIQUE - which is not "raking" or slap or spider or any of that other crap. All technique means is your physical approach to the instrument. You need to have a physical approach that is always relaxed and tension free, that assures you control over all picking/plucking, fingering, shifting, phrasing, emphasis etc. You never want the instrument to be an impediment to getting to the music.
2. UNDERSTANDING - or music theory, but primarily functional music theory. How chords are bulit, how they function, how they relate to each other
3. HEARING WITH CLARITY - ear training. Hearing, identifying and singing intervals in the first octave, the second octave, triads in open and closed and all inversions, 4 part chords in open/closed/all inversions. 4 parts with 1 tension, 4 parts with 2 tensions. Trascribing, sure, but not for datamining. All to get to the point that when you hear something inside, in your musical imagination, that you can use #3 to clearly identify what you are hearing, use #2 to understand WHAT IT IS that you are hearing and #1 to get it out into the air so everyone else can hear it too.
Sight reading is probably one of the few things you can work on without someone guiding you, just grab everything you can - Bach 2 parts, trombone etudes, etc - and have at it. Instead of reading a book or the newspaper, grab some music. If all a teacher wants to work on is supervising you sight reading, I'd look elsewhere....