The one thing I pushed off for as long as possible. Because it was always easier to build more, than it was to go into marketing / sales.
No clever tricks, or growth hacks. Me and my cofounders just connected with everyone we could on LinkedIn, twitter, discord, etc. and talked to people about the product: https://rysolv.com/.
In fact, part of the reason we delayed marketing was looking for some clever way to 10x, or make it go viral. A big motivator was Paul Graham's "do things that don't scale" post [1]. So we just sat down and talked to people.