In Dance Central 2’s Crew Challenge, how do you change the dancer for a particular song

The suggestion I got from my resident Dance Central expert was that the Kinect has trouble recognizing you when you have parts of your body in front of other body parts. She suggested starting with your upper arm closer to parallel to the ground, so that the Kinect can pick it up, before you move it across the front of your body. Keeping your arm further in front of you as you move it across your body will also give the Kinect a somewhat better chance of catching it.

She also suggested making more exaggerated motions. "When doing that move, I always felt like a cheerleader - super exuberant."

I had trouble with importing the DC2 songs into DC3. Although it accepted my code, once it finished downloading the key it just left me hanging with no further instructions, and the songs didn't appear.

What I discovered my problem to be was that I had entered the code while signed into my son's account, which was set up so as to not have permission to buy content and which also didn't have any Microsoft coins associated with it. When I changed those settings and added coins to his account, and then re-entered the code, it finally gave me the option to purchase the import pack after the download completed. (I did have to re-enter the code -- simply re-downloading the key didn't work.) I authorized the purchase, the songs downloaded smoothly, and they showed up in the game once the download was completed.

So apparently when I had initially entered the code, even though it apparently had been accepted, it hadn't really taken and what had downloaded wasn't really a functional key. It would have been much more helpful to instead get an error message along the lines of "This is a correct code but the game cannot accept it because your account is not authorized to make purchases."