Besides making catchy pop tunes that appeal to a larger audience without much innuendos followed by a crafted image that puts her as a sexy symbol and yet fun relatable ordinary girl and a perfect marketing team, it just seems that she/they make absolutely no wrong choices.
She's been slaying since her debut, while pop girls have come and gone.
Seriously though, her marketing team. They were completely on top of everything in TD and the singles smashed. They've dropped the ball on some of Prism's, and they accordingly flop. The ones they did well with (Buzz Single Roar and First Single Dark Horse) have both been very successful