If only it we're as easy as someone telling you exactly what to do and voilá, the customers would just appear. In reality very few startups actually fail because they can't put together a decent product and very many fail because no one ever hears that they exist. There are a great variety of different customer acquisition channels you can try. If you get one channel to work, you already have a good business. If you get more than one to work, you have a fantastic business. I'd recommend reading online about customer acquisition channels.