An Exercise

Here's an exercise I invented today.

Take the the chord change I vi ii V7.  It is a very familiar one used in numberless songs.

Play it again, but this time as I vi II7 V.  Now you've taken the relative minor, or vii, and imagined it as the ii of the the V. You have modulated to the dominant or V chord.

Now take that chord and treat is as I, and repeat the same sequence all the way through the circle of fifths.

So

C a d G7
C d D7 G

G e a D7
G e A7 D

D b e A7...

etc....

Now you will know relative minors, I vi ii V7, and ii V7 I, in every key, in a mere 96 measures or fewer depending on what harmonic rhythm you want.