Writing can never be anything other than a lonely business. In the initial shaping of what you write, you’re going solo.
If that’s true, then of what help can outside influences be? How can instruction help? Three main answers.
First, the problems common to all writers are predictable. It’s not as if every writer’s struggles are unique. Coming to understand this truth is itself a major help.
Second, the best writing comes when you want to write. You must genuinely yearn to get your point across to others. The question, then, becomes how to prompt this feeling—how to become excited about creating a first draft. Replicating this sensation will vary from writer to writer, but knowing that it’s a universal need is beneficial. You can learn to prime yourself to finally sit down and write.
Third, you can intelligently apply many kinds of learned techniques: meditating on what you’re about to produce; strengthening your understanding of how a principle applies to crucial facts, or rather how those facts make the principle apply; mastering the art of orderly exposition; improving your use of words, which are your only tool; learning to read with an eye to duplicating the smart rhetorical moves of people who write better than you; and learning never to be unduly impressed with your own first effort, which will inevitably require improvement.
Imitating your betters is essential. So you must become a serious and constant reader. Without that, your hopes of writing well are for naught. But will this hamper your originality? Absolutely not: in the long run, you’ll never write like anybody but yourself. It’s just that if you manage your writerly habits well, you’ll become a better version of yourself.