I'm just parroting what other people say—<p>If it's a startup, a thing you're trying to make money on, or a community-oriented thing, market your app before you start. Marketing looks like talking to ppl you think are or will be interested in it. See if what they tell you about their needs fits your own understanding of their needs, and if it does, tell them what you're doing. If it's a paid app, see if they'll give you their name/email.<p>If it's a side project, go ahead and build it, or at least a simple first version of it. Then demo it around to see what people think. Twitter, Discord, Reddit, are great places to find tons of ppl into anything you're wanting to build. Sometimes, in-person meetups are great for that too. For example, my side project is a job board in the vein of japan-dev that was posted here last week. I just put together a prototype and formulating an idea of how I explain the value prop of it.<p>Mostly it'll be some form of the two — get some idea or prototype out, then see what people think. This will usually inform you what ppl are excited about.<p>I haven't considered search ads and Show HN or Product Hunt yet — I think I want at least 50-100 interested ppl, and maybe some initial traction before going that route. It'll either be a firehose of criticism or love... but it's a firehose either way.<p>Basically make sure your wheels are properly attached before you go down the ramp... but don't spend TOO much time attaching those things :P