Possibly related: at one point I was spending lots of time on mailing lists. In particular lots of time composing long replies.

At one point I noticed something: I was replying to things that weren't questions.

I taught myself to notice whether what I wanted to respond to had the useful punctuation that some human languages use to signal a question: "?". If I didn't see that, I wouldn't write anything in reply.

Now I was spending much less time on the lists.

(This was a good first step, but what you're talking about in the above - noticing when you have questions - seems harder to me.)