Take heart: Nobody springs from the womb with DaVinci's fine motor skills.
That said, some people are just wired with an intuition that applies really well for translating three-dimensional visuals into two-dimensional visuals. I think I watched a documentary about artistic savants where they attached electrodes to the heads of non-savants and pulsed something into their brains after and before they drew the same thing. The drawings after the electro-shock treatment were strikingly better than the ones before.
But I'd prefer to just keep practicing, because, as I said, nobody starts out good at drawing. There was a television series I used to watch called
The Imagination Station where a cartoonist taught viewers how to draw and I learned a lot from that...even though I didn't want to be a cartoonist, I
did want photo-realistic DaVinci style drawings with perfect proportions and shading that makes it come alive, and everything that wasn't and isn't that is just proof of how innately awful I am at art!
Mostly, though, I draw because I feel like I need to. I think that can help a lot with practice, the feeling that the creative force is somehow bigger than yourself, so any effort to get it out there at all is worth the embarrassment at the quality. And, sometimes, I look at something that I drew, and it's no DaVinci but I just
like it. And then I look at drawings that I did before, and I might like them and I might not, but I can compare and see where I'm getting technically better in general (although I might have produced something on a lazy day, where I just didn't have my head in the game. Generally, though, practice does make improvements.) And that's very encouraging.