The only way you’re going to understand the people who might use your product is if you talk to them first.
In order to design a truly relevant, useful and successful product, you need to clearly understand your potential audience. And the only way you’re going to understand the people who might use your product is if you talk to them first.
There are many different types of user research. You can go out to observe and interview people in their own natural environment (which is documented in this collection of user research war stories), you could invite people into your office to be part of a focus group or hold one-on-one interviews.
Alternatively, you can run UX testing on your prototype, in order to get some early insight into how people will use your product. Bear in mind it’s much easier and cheaper to change a prototype than a finished product.