JUST DANCE 2015

I used the song "You spin me round and round". It is one of the easiest to get perfects, and there are good videos from people dancing it.

Moves that can be problematic: In the gold move, remember to not only point at the screen, but also advance your right foot a little. This will help the gold move to register and help in getting a perfect in the next move.
When you need to turn around with your arms up, I found out that going one step left, one step right, without turning but with my arms raised, actually gave me better results.
Be careful at the end of the song. There is one last move after it seems over.
The turning around with one arm pointed is perhaps one of the most annoying parts. I had to do it actually turning and without really looking at the screen for a moment. On the other hand, it is not a difficult move to get perfects if you time it right, which means keeping track of what you should be doing by listening to the song and not looking at the TV.
Last but not least, some moves require a good energy explosion to get perfect, like the one jumping and dropping your arm. If you are tired, you might start getting only "Good" in these moves because you didn't jump or raise or arm all the way. If this start to happens, take a break and try another time.

Know all the moves in your head. If you have to wait for the person on the screen to start, you are starting after her, and therefore you are already late. Start the move at the same time, and for this you must know what comes next.

Don't get frustrated: this can take a long time to get, especially because you will get tired and won't be able to play for hours straight.

I got this achievement and the one for only "Perfects" and "Good" moves together, so you might want to try to get both, as practicing for one helps with the other. However, if you are full of perfects and gets one "ok", don't stop, you might still get this one at least.