How to Find Notes
The easiest way to break down finding notes on the guitar is to simply learn the dotted notes on the lowest two strings (E and A), and then learn the basic shapes to help you find all the same notes.
The dots on the Low E and A strings are the first thing to learn. Each fret moves you one note higher or lower. The notes on any string are determined by the open string, that is, what note the string is when you don't fret it (e.g the Low E string is an E note when played open, therefore the first fret of the Low E is an F note). The order of notes in music are as follows:
A, A#/Bb, B, C, C#/Db, D, D#/Eb, E, F, F#/Gb, G, G#/Ab, A etc..
Remember: Sharp (#) = UP Flat (b) = DOWN
Blue Cats Eat Fish = No Accidentals between B and C, or E and F
From each note on the Low E and A strings, if you just go up two strings and up two frets, you will find the exact same note an octave higher. This can also be done in reverse (if you're on the D or G string, go down two strings and back two frets and you'll find the same note an octave lower). Because the B string is tuned slightly different, this shape just increases by one fret when you use the B string. All that is shown here:
The Major Scale
When starting the major scale on either the Low E or the A string the shape stays the same. What changes is the root note. For example, if you started this shape on a B note, it would be the B Major Scale, and the notes in the shape would be the notes in the key of B Major. This scale will be the main point through which we will understand how chords and keys work, analyse other songs and expand your own creativity on the guitar.
Using the note finding techniques above, you have everything you need to be able to start this shape on a particular note (in this diagram G) and figure out all of the rest of the notes in the key. In G it would be:
G A B C D E F#
The Minor Scale
The 5 Root Shapes
Across the fretboard there are set shapes between one note and the next. On the diagram below are outlined the 5 basic shapes we can break these down into. These shapes apply no matter the starting note, and always follow eachother in the way displayed here.
Finding Intervals and Building Scales
As there are ever-present shapes between the same note across the neck, there are also consistent jumps across strings to reach the next note. A 'Whole Step' (2 notes) is 2 frets on the same string, but to make the same jump from one string to another, you have to go back by 3 frets on the higher string. To do the same but for a 'Half Step' (1 note), you need to go back by 4 frets on the higher string. As the B string is tuned differently, these jumps are all reduced by one fret when crossing from the G string to the B string, as shown below.
Once your comfortable with these fretboard patterns, you can begin to build and learn your scales across the entire fretboard with only two steps:
1) Know where your roots of the key are
2) Know the intervals between the notes in the scale you're using
We have looked at both major (ionian) and natural minor (aolean). The scale degrees for these scales are as follows:
Major - 1 2 3 4 5 6 7 (8)
Minor - 1 2 b3 4 5 b6 b7 (8)
Therefore the jumps between each note of the scales are:
Major - R W W H W W W H
Minor - R W H W W H W W
Combining everything we have looked at so far, here are the main scale shapes for both major and minor in each of our 5 root positions, in both G Major and G Minor.