Natural talent combined with lots of practice.
Without both, no one is going to be at the top of what he or she is doing.
But most importantly is: always have fun, and if you dont, either you should reconsider how to have fun or stop it, or better be paid for it
I know I cant pass up to the top levels of sim racing, I didnt even finish all license test (okay, just 1 gold is missing) or missions (I can not understand how to drift in GT7). But whatever I am doing, I am doing it without feeling to miss out particular things of the game.