Writing is a discipline as much as a skill: There’s the discipline of sitting down and writing each day, whether you feel like it or not. There’s the discipline of editing yourself, and not putting up with any nonsense. There’s the discipline of keeping on writing, even when some inner voice is telling you it’s terrible and should never see the light of day.
Sometimes that inner voice is right; and you should learn to listen to it — judiciously, and at the appropriate time (i.e., after the piece is finished).
So, yes, writing is a discipline. But again, it is also a skill. One you learn through practice and experience – and reams and reams of patience. Not to mention, it’s also an exercise in humility.
Anyone who’s going to write well needs to learn humility from the get-go (some of us are still learning). But humility doesn’t mean false modesty, it means a keen observation of reality, avoiding both the tendency to puff your own ego and the tendency to beat yourself up for perceived “failings” and “flaws” (many of which often turn out to be imaginary, or just a sign that you haven’t been sleeping lately).
It means being realistic about your faults, and working to correct them in practice. But part of that means you don’t stop publishing meanwhile. Sometimes “good enough” has to be, well, good enough (for now).
You give it your honest best, you iron out any typos or errors you’ve made along the way — maybe even cut out a paragraph or two that you may have rather liked, but which really had no place in the piece as written — and then you publish it: you send it out into the world, and start work on the next one. Or have a rest for a moment, and sit back with a cup of tea, put your feet up, and relax …
… until the next piece comes along as an idea insistently poking at the inside of your head and demanding to be written.
It’s a dog’s life being a writer …