Who are you really? If you know that, then you know what you can be best at. It is not easy to know who you really are. To know who you are, you need to first know who you are not. To know who you are not, you need to try a lot of things.
The more stuff you try in life, the more you can eliminate until you find the one thing that defines you. The one thing that you feel you are born to do. If you want to be best at something, find the one thing that you feel you are born to do and then practice that relentlessly.
We humans are very good at learning skills, even the ones where our heart truly does not belong. We get good at it; we might even think we are best at it. But, when we find something we really love and we sink our heart into it, we truly become the best.
Never stop singing to the tune of your heart. Because in that song may lie the path to finding who you truly are.