Fretboard and Theory
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#
Making Chords from the Major Scale
A little on chords themselves: a major chord is made up of three notes, 1st 3rd 5th (from it's major scale). A minor chord changes slightly and is made up of 1st b3rd 5th (the 3rd is dropped by a fret). You can see this in any given open chord major and minor pairing.
That being the case, we can turn the notes of the major scale into full chords by taking each degree and finding its relative 3rd and 5th. Following that process we get:
1st - Major
2nd - Minor
3rd - Minor
4th - Major
5th - Major
6th - Minor
7th - Diminished
Therefore if we took the G Major Scale, the chords in the key of G Major would be: G Am Bm C D Em F#dim.
Just like in the scale, these chords would naturally resolve to the root (G).
Some common major keys in songs: E, G, C, A, D
There are a few methods to use to determine what key a song or progression is in.