1. You play a major scale, any key you want to name.

do re me fa so la ti do

2. You play it again, noting which note is #6

do me me fa so LA ti do

3. Now play the same notes, but this time you start and stop on La, formerly the sixth note. Remember, you keep the same sharps and flats as in step 1.

4. You have just played the relative minor scale for whatever key you chose key in Step 1.

5. Play the minor scale again, but this time, slide your finger up and make the 7th note one half-step higher. That is the 'harmonic minor,' or as we call it at my house, 'the belly-dance minor.'

Some popular major keys and their relative minors:

C Am
D Bm
G Em
F Dm
A F#m

Of course, people are free to use the other notes, either black or white, that we have on our instruments. However, using too many of them leads to music which sounds more like machinery than like music, and while we pay tribute to the creativity and prestige of the people who wrote it, we don't actually want to listen to it.

Finally - sometimes people think that if a song looks to be in C, but it sounds minor, then it's in C minor. No, it's not, it's in A minor. As somebody said above, Cm is the minor for the key of Eb. It is not a favorite key around here.