Any tips on growing Newsletter to 1000s of subs?

Over the past couple of months, I've been able to grow my newsletter to a couple hundreds subs.

However, this was mostly due to 1 popular post shared on hackernews that discussed the backend of our newsletter that we built.

Any tips on growing to thousands?

What do you do on a daily basis to grow your subs?

Note: We are in the Tech & Finance space