I have been very focussed lately on learning all the note positions on the fretboard. I use a variety of techniques gleaned from various sources (including this forum) but what has really moved me forward is when three days ago I ...
...named my BASS 'GABE'
in fact I named it G A B C# E but kind of ignore the C# on the 9th fret (but I know its there cos I can see it)
How and why :
I used a label maker to place a tiny label on all the dot frets behind the neck. (I can still see the dots so they relate to the G A B C# E)
What this has done is give me a very visual "memory anchor" at the E string from where I can quickly , mentally map the rest of the keyboard by the basic patterns of the chromatic scale and the sequence of notes.
eg I know EADG is the open strings and it is the same at the 12th fret. I know BEAD is at the 7th fret . I know the entire chromatic scale on the E string ...so already that was a lot of fretboard notes that I had sorted.
Filling in the rest is real easy from this base
A few other little things I had learned previously really helps in this as well. eg string tuning at 7th fret, octave spacing , a couple of major scales etc.
I also practise with a full fretboard map open in front of me that I can cross check myself as a little test.
With the little GAB*E thing I can easily mentally visualise and learn my notes even without the BASS in my hands.(like in bed at night) I even notice that I am naming notes as I play little riffs and musical exercises.
Works for me. Hope fully of value to someone else.
BYW - I hate having the 5 little stickers defacing my bass but thats incentive to get the task done asap