When building a software product, it's important to figure out the individual pieces in a small market microcosm and make sure that the product works for the desired market BEFORE you go about worrying about scaling. This is another way of saying -- avoid the build and they will come strategy. With software and mobile products, entrepreneurs often focus on scaling the product before they've really figured out the dynamics of consumer interaction and satisfaction with your product.
Nailing a product is hard work and takes time and a lot of attention to detail. Figuring out when and if you've nailed the product requires lots of feedback. Focus on refining the minimal feature set and the customer feedback to determine if you're being successful.