You have to clear 800k points to earn the 5-star if you're using the controller, and something in the neighborhood of 500k if using the Kinect sensor. The key is to keep your multiplier at x8 for as long as you can. You want to octo-lock as much as possible and release it with the beat of the music to build/maintain your score multiplier. It's tough, but with practice you can achieve it. I found the Passion Archive to be the easiest. YMMV.