I am still focused (obsessed) on learning the fretboard. My latest attempts involve playing all notes (not including sharpe and flats) in every position on the fretboard. So I play all to the notes from low E to high E. Then I do the same with A, etc and continue with all the notes (E, A, B, C, D, F and G.) Then I try to play each note selected at random, in all positions. Next I play major scales of C, D, E, F and G n several positions. Finally I apply what I have learned to a new piece of music by selecting the appropriate frets needed.
Initially didn't't think that I was up to this because of my age (almost 79), but for unknown reasons feel a strong compulsion to become proficient in this. No single technique works for me. For example playing scales in 3 positions does not help me know what are the options for playing F (174 Hz).
I don't expect anything to happen overnight but there is some progress. I am trying to get this fixed into my permanent memory (if there is any left).