I would say both. You need to learn by trying things out, making your own mistakes and finding a style. Then you get input from the outside world on why some peculiar structure make sense or just giving helpful tips. Then you try out more, apply those tips and see what works for you. But you can read as much helpful input as you want, it won't be any good without you trying to apply it and practice.

At the end of the day, both are required. You need to study to be effective at what you're doing, but at the end of the day the only way words get on paper is writing. You'll also get more out of learning these structures and ideals trying to apply them after you have a bit of time just floundering, getting a feel for the actual task.