Authenticity is an element of style. Realness. Not confidence, as everybody likes to think; no, confidence is an illusion of style and nothing more. A 'fake it till you make it' example. But pure feelings and characteristics lead to style. These can include confidence, but confidence does not equal style. Style has to be genuine. You have to really stand for and believe in whatever you're putting out there for you to achieve true style. You have to have an strong opinion.
Everyone is always going on about "effortless style" — we all know it when we see it; Parisians tend to come to mind for me — and that style is usually the result a person just living their life. It's effortless because it's completely unintentional, natural, and easy, and it's style because since they use it in their life, they've had time to perfect it. It's not something wild that you'd see walking down the runway, but rather something that wouldn't be out of place walking down the street; something that can be worn for daily life.
Style is not overnight, style is not permanent, and style is constantly evolving. You don't get a signature look overnight, you won't keep that exact look forever, and you'll probably keep changing it.