Chromatic scales. For each string on the guitar play the open string followed by the notes on the first four frets consecutively low to high. If you are keen say the notes as you play them. This exercise is for building co-ordination, strength and making a decent sound. Spend a minute every day playing 1 2 3 4 on each string. Soon you will be able to play all the notes in the scale.
Open strings on the guitar from low to high are E, A, D, G, B, E. Eddie Ate Dynamite Good Bye Eddie.
Use index, middle, ring, pinky on four frets. Always play the same fret with the same finger. On the low E string this will be F, F#, G, G#
Fingering the Diatonic Scale
Diatonic scales. Put your middle finger(2) on the fifth fret of the low E string. By now you know this is A the next note after G#. Play 2 , 4 this is Do, Re and you are out of fingers. Play 1 on the next higher string, trust me, this is Mi , now Fa is the next note so play it with 2, play So with 4. we are out of fingers so on to the next string play 1 this is La, 3 is Ti, and 4 is Do, the octave.
2 4 — 1 2 4 — 1 3 4 — finger number
Do Re — Mi Fa So — La Ti Do — note
This is the fingering of the diatonic scale on three strings. Do is the first 2 and this is the root of the scale. Notice how Mi Fa and the final Ti Do are consecutive fingers. This lick will produce a major scale almost everywhere. So learn it as Do Re Mi and as one thru seven. Notice that by focusing on fingers and not on notes you avoid thinking about sharps and flats.
Furthermore this rule allows you to use your guitar as a slide rule( a primitive calculator) to derive the notes in any scale. Just play the scale starting at any root and observe what notes of the chromatic scale your fingers land on.
Try it here and there around the neck. It always sounds a major scale unless you move to the B string in which case you move the shape up a fret but otherwise keep the same fingering.
Having this fingering in muscle memory means that if you learn a lick or a phrase as a set of numbers, say 1 3 5 3, Do Mi So Mi, which is a good base line for any chord in 4 4 time, you can play that sequence in every key all over the neck and the intervals are the same only different in pitch. For those who already know solfage because they sing in a choir this approach will be familiar.