Hey Friend,
Yesterday, we identified the notes that make up the key of E major. I said that today we would look at the harmonic scale, but I think the more appropriate term would be harmonic progression.
A scale presumes we're using individual notes, whereas a progression can indicate something else such as the triads (chords made of three notes) that come out of that scale.
Starting with the E major scale, we get a good idea into what the chords might be.
E F# G# A B C# D# (E)
Looking at that series of notes, we know what the root note of each chord will be. Now it's just a matter of applying a pattern to the notes to identify the chords. Here is the pattern:
M m m M M m dim (°)
That is:: Major minor, minor, Major, Major, minor, diminished
Memorize it, learn it, love it. The harmonic progression for any major key uses this pattern to determine the basic chords. Here it is applied:
I IIm IIIm IV V VIm VII° E F#m G#m A B C#m D#°
See how easy it is to figure out what chords you should use in a key? It's like simple algebra - pattern A plus pattern B equals the harmonic progression.
pA + pB = HP
Now let me be clear on something. It's not actually the pattern that determines the chords in the key - it is the notes in the key. Each one of the chords listed above (in the key of E major) can be constructed using only the notes of the E major scale.
Check me on this...
An E major chord (E) uses the three notes E, G# and B.
A G# minor chord (G#m) uses G#, B and D#.
A D# diminished chord (D#°) uses D#, F# and A.
Make sense? Write out the rest of the chords in E major this way. See if you come up with the same results. Let me know your questions.
Peace~
Dave | 
