Watch the Harmonic Minor Scale online guitar lesson by Bruce Arnold from Total Modal

The Harmonic Minor is used over a minor Major 7th chord. A Harmonic Minor Mode can be superimposed over a regular minor chord. You can find voicings for (-?7) in the previously recommended Chord Workbook for Guitar Volume One. The Harmonic Minor Mode has no avoid notes.
Modes should take up 30% of your practice time each day. Think of your first time through these modes as just an introduction. Do not try to master each mode as you go. It's very easy to get discouraged as you learn modes because there are so many. By just introducing yourself to each mode you will become familiar with the mode and it's sound. Once you have gone through all of these modes in all keys it's time to move on the Total Modal 2 which will give you alternate ways to play and apply scales. I mention some of these more advanced concepts at the end of this introduction.
I often tell my students to organize their practicing by concentrating on one mode in one key per week. If you have more than an hour to practice each day I would suggest doing one mode a day in one key. I recommend going through all the modes in C first so that you have an idea of the sound of each mode. So start with C Ionian then C Dorian, C Lydian etc... and continue through all 19 modes.
When you have played all the modes in C major you want to start the process over in the key of F. Progress through the keys in the following sequence (cycle 5):
More specifically you should do the following:
1. Each day play the scale(s) in all 7 positions
a. Think the names of the notes (i.e. C, D, E etc.) or the degrees of the notes (i.e. C is the root, D is the 2nd, E is the 3rd etc.).
b. Play the mode over a jam track so that you hear the mode in relationship to the way you are thinking of the mode. For example if you are playing a C Ionian mode and you play an F this note should sound like the 4th degree of the key center. It is of the utmost importance that you develop the ability to hear these relationships as second nature.