The in-key pattern
In common music, most notes used are 'in-key'. Then, chords (multiple notes played at a time) are built from these in-key notes. There are only twelve notes in music, but they repeat in 'octaves'. Only seven of these notes are in-key. Below is what the pattern of in-key notes looks like. Scroll horizontally to view the entire pattern. This pattern repeats infinitely up and down so the ends 'connect'.
The in-key guitar pattern
We can apply the in-key pattern to the guitar. Each dot on the fretboard below is a note that is 'in-key'. This entire pattern repeats up and down so the ends 'connect'. The pattern is not specific to any note or fret number - it can be shifted up or down depending on the 'key' you are in. Scroll horizontally to view the entire pattern. Tap a 'Degree' and 'Type' to highlight specific notes or chords inside the pattern. The most common chord progressions in typical songs use primarily the 1, 4, 5, and 6 degree chords. Most common songs will resolve back to the 1 (Major) or 6 (Minor) degree chord. Once you find the 'root' of a song, you can play any of the notes in the entire in-key pattern and it is likely to sound good.