I've actually just written some tips in "5 tips to grow a community before your launch": https://www.producthunt.com/disc...
Summary (there's more in the post!):
1. Find where your target audience hangs out
2. Join communities of makers
3. Don't be shy and reach out to people
4. Collaborate with influencers
5. Create content online
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Kypso
Kyligence Copilot