I think there might be two main factors in achieving your dream: firstly, to be convinced it is something worth fighting for. Secondly, fully believing it is possible to reach your goal.
Of course luck is also a factor, but it's just a waste of time thinking about is, as you can't influence it. Rather focus on the things you can change.
That being said, I've no clue what I want to do with my life, as I'm not sure what's worth fighting for to me.
On the other hand maybe there's never a point in our lives where we figured it all out and we know what we're doing.
Maybe waiting for that clarity is just wishful thinking and the most successful people are the ones who have the courage to move forward despite the uncertainty.