By customer-driven, I mean the first talk to customers, then code. Understand what kind of job your customers are doing (don't talk about a product, just try to understand your customers), for example, people who study Chinese what kind of day to day tasks/job/activities they do related to learning Chinese? What gives them the most pain/problems? Is there anything that you can do about it?

Before trying to sell, try to understand your customers. If you really solve an important problem for them - people will pay.

I don't agree with "rich people statement". I started my first web-consulting company by self-learning how to code websites and then lived in a shitty room in Russia with my girlfriend, barely making money for a rent and food. I found first customers by browsing and phone-calling through local classifieds.