Ozy tells 80,000 Hours how to write Substack posts
Read my advice for succeeding on Substack here.
Here’s a sample:
Broadly speaking, there are two approaches to Substack: you can make a serious attempt at a career as a Substacker, or you can write intermittently whenever you have something to say. I think very few people should make a serious attempt at Substacking as a career, and a lot of people should consider writing intermittently.
If you notice yourself explaining something over and over again, you should write a blog post. People interested in high-impact careers likely have a lot of thoughts about the world’s most important issues, ranging from the broad and philosophical (cause prioritisation) to the extremely specialised (flaws in specific studies everyone keeps citing). If you post them publicly, people you don’t know can also benefit from your knowledge and experience. It also saves you time because now you can just send someone a link. Good public writing can also be a source of career capital: people stumble across your post and conclude you know what you’re talking about. (Of course, by the same token, bad public writing can harm you.)
Substack is designed for news, not for posts people will be reading in five years. Reading a Substack’s archive is a pain, and most Substacks are poorly indexed by Google. Therefore, if you take the intermittent-posting approach, I recommend posting to both a Substack and a separate stand-alone website (for inspiration, consider Andy Masley or dynomight’s pages). Your Substack allows people who are interested in your thoughts to subscribe and be automatically notified when you have something new to say, while the stand-alone website serves as a canonical reference.
In the rest of the post, I’ll assume you’ve decided to try to Substack professionally…

Substack seems to really reward consistent authors who produce a lot of content. Seems like a bad platform for occasional one-off posts which will languish in obscurity.
If you want people to write more one-off posts you should offer to publish them on your stack as guest posts.