The way I learned was a bit slow and methodical, but really clicked, and helped me learn the cycle of 4ths/5ths too, I forget where I picked it up though:
1. Write/print the notes from the circle of 4ths out (C, F, Bb, Eb, etc.)
2. Set a metronome at some super slow speed (like 40-60 BPM)
3. Go...