Short answer: pick one narrow kind of buyer, talk to them before you sell, and answer the people who are already asking for help with the problem you solve. Then onboard the first users by hand. Ads can wait: they scale a message that already works, and at the start you don't know yet which message that is.
1. Pick one narrow buyer
"Small businesses" is not a buyer. "Bookkeepers at 5 to 20 person firms who reconcile invoices by hand" is. A narrow buyer tells you where to look, which words they use and what to say first.
2. Talk to ten of them before you sell
Ask how they handle the problem today, what it costs them and what they have tried. Don't pitch. Start with people you already know, then people in the communities from step 3. Their exact words become your landing page and your replies.
3. Answer people who are already asking
Somewhere right now someone is asking for help with your problem on Reddit, Bluesky, Hacker News or X. A useful answer there reaches a person who wants a solution today.
- Find the communities with Website to Subreddits or a best subreddits list.
- Search for the problem, not your product name: how to find those threads.
- Check each community's rules in the subreddit rules checker before you mention your product.
4. Give something away that solves a slice
A free tool, template or checklist that solves one small part of the problem is something people link to and share. Ours are the free tools: no account, and each one points at the bigger job.
5. Onboard the first users by hand
Set up the first accounts with each user, on a call if they'll take one. Watch where they get stuck and fix that before you look for more users. Ten people who use the product every week tell you more than a hundred sign-ups who never return.