In short, it's all about spending a bit of time finding out where there is a high density of people within your ICP and studying how they do product discovery.
As soon, as you've done that and narrowed it down to 2-3 distribution channels/tactics (Could be Reddit Sub Threads, Product Hunt, and Twitter) then I would go all-in on those 2-3 until you can either confirm or disprove that it's the...