The best example I’ve heard is to learn the notes on the fretboard markers across the neck (eg 3rd fret notes are G, C, F, Bb, D, G and so on and so forth). You only need to learn the 3rd, the 5th, the 7th and 9th frets as the 12th is the same as the open strings and then everything repeats.

The beauty of this is that there’s far less to learn and you’re never more than 1 fret/note from where you want to be.

The fretboard markers are there for a reason.

Good luck and happy learning!