I've been playing for about 15 years, started late, am now 42. I play in a professional band for hire (weddings, karaoke, corporate etc.) and another more artistic project. I'm happy with my playing and get a fair amount of compliments on it, but I'm still not able to improvise as freely as I'd like or look at the fretboard and know what the notes are going to sound like before I play them. I can do it slow but it gets squirrelly as things speed up. That said, my fretboard fluency has increased dramatically over the last year from practicing arpeggios in the II-V-I format. I'm also an intermediate player on upright and that has helped with the geography as well. I'd love to hear from some of you what if any one or combination of things took your playing to the next level (please don't say "practice"). Was it learning a particular tune in multiple keys, practicing double stops, singing what you play etc.? Thanks.