A kind of post I would like to read more of is "I did X, and here's how it went." You tend to see this most with research, but I've enjoyed reading them on all sorts of things. This is one of the main kinds of post I write, and I would encourage others to give it a try!
Here's an arbitrary selection of writeups I've enjoyed:
Major reasons I like writeups include:
Exposure to problems that I didn't know were important to people.
Detailed looks at how people handled problems.
They're generally very concrete and written after the fact, which makes it harder to write something that's neat but wrong.
When I'm thinking of doing something and find a writeup by someone who did something similar it's fantastically useful.
When you voluntarily make something public, you do risk that people will irresponsibly beat you up over failings. I think it's generally worth it to go ahead anyway, tell the whole story, and help build a norm of sharing things so others can learn.