Just Dance 4
40 Achievements
1,000
60-80h
Xbox 360
Reflection of Perfection
Complete a Song with 80% or more Perfect Moves
30
How to unlock the Reflection of Perfection achievement in Just Dance 4 - Definitive Guide
I found this to be most easiest on the sweat programs. In between each of the songs you will have to do a dance routine with one of the excercise instructors. Their moves are pretty simple and very repititious, plus the game seems to be more forgiving on the tracking of these sessions. Once you have the patterns down you will get this in no time!!
This goes along the same lines as You got the Moves!, but you will need to get an almost perfect run on a song. Although this sounds tricky, it's very likely that you'll get this whilst working towards the Megastar! trophy.