There are marketers and there are product makers. Ok, some people are in between but you know what I mean. Business people tend to think about reverse-engineering market demand. On the other hand, hardcore designers/developers begin with a shiny product idea. Often, these product makers will struggle with growth. When their product isn't just an art or science project, they have a hard time turning the passion into a real business. What's your top growth hacking advice to a hardcore designer/developer who builds things based on their ideal product visions?