I lot of self-help type advice advocates a positive attitude, just thinking you can do something. But how do you really know you can do something? Maybe you can't and the advice to have a positive attitude, an empty optimism, will be next to useless.
So how do you know you can do scholarly writing?
In the first place, you might not have a realistic notion of how hard or easy it really is. If you think of it as easy, you might get into trouble by being overconfident. On the other hand, if you think of it as impossibly difficult, you'll never get anywhere.
It's something that a lot of people do, and it's not very difficult at the lowest levels. Publishing a graduate student seminar paper in a second line journal, for example, is not infrequent. On the other hand, rising to be one of the top scholars in your subfield is fairly difficult.
So it's a matter of breaking things down, reverse-engineering top articles in top journals to see how it's done; evaluating the state of a field to see who the best people are and how they got that way. In my case I could see that there were a lot of crappy to mediocre famous scholars in my field, so it was simply a question of putting in the work to do it better. I would automatically be at least among the top few simply by reading more and better and writing it up.
We've all known academics who aren't very smart. We've all met academics who are so intellgent that it hurts to even think about them. The thing is, you don't have to be in the latter category to achieve what you need to.