Apple keeps it very close to the chest, a lot like Google does with their algorithms. If people know what makes rankings rise and fall, they'll inevitably find

Apple keeps it very close to the chest, a lot like Google does with their algorithms. If people know what makes rankings rise and fall, they'll inevitably find a way to game the system. The only things I've seen that definitively affect rankings is downloads and ratings. Sales affect the top grossing rankings only.