What's the worst ProductHunt launch day mistake I can make?

Make a checklist and stick to it. Try not to deviate and do a bunch of stuff, all at once.

Hi KJ! once you launch your product you have to be sure that your don't ignore you the most important thing; engaging. The worst Product Hunt launch day mistake is failing to engage with the community. Ignoring comments, questions, and feedback can alienate potential users and diminish your product's visibility and credibility. Hope this helps; :) Good luck to you on your launch.