Scale Theory
I should begin by explaining how the major scale is created. The first note of the major scale is name of the scale. By that I mean a "C" scale starts on a "C" note. An "A" scale starts on an "A" note, and so on. There are twelve different scales if you don't include double flat or double sharp scales. Are you with me so far?
The twelve major scales are:

C, C#, D, D#, E, F, F#, G, G#, A, A#, B

The C# D# F# G# A# notes also have "enharmonic" notes related to them. By that I mean the C# is played in the same place in most instruments as a Db note. They are the same pitch; they just have different names. The tricky part is that a C# scale has a zillion sharps in its key signature, and the Db scale has a bunch of flats - plus the C# scale starts on some kind of a "C", where the Db scale starts on some kind of a "D". So even though the scales are played on the same place on the fingerboard, the notes have different names depending on whether you are playing C# or Db. I'll show you why in a minute.
The "C" scale is the simplest one of all, because there are no sharps or flats in the scale:

C D E F G A B C

These are the white keys on the piano in order. The distance between each note of the scale on the keyboard or fingerboard determines the structure of the major scale. In the C scale, "C", as I said before is the first note of the scale. "D" the second note of the scale is two steps (frets) higher than the "C" note. The distance between two notes is called an interval, and a two-fret distance is a whole step interval. The next note of the scale is "E" which is a whole step away from the "D". Have I lost anyone yet?

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