User-centered design is a set of processes that help designers get in the headspace of the user when designing a product. It's a powerful tool that designers can use to create a naturally intuitive product that requires little memorization and is accessibility-friendly. Without user-centered design, it's much easier for products to turn out unwieldy and frustrating.
The first thing you need for the user-centered design process to work is a clear understanding of your users and what they need this product for. What components will this product need, and how can they fit together as intuitively as possible?
During the various stages of development, you should incorporate user feedback. This will help ensure that you're on the right track and give you real-world data to lean on.
Getting users on board early on will help you create a product in line with their needs and level of understanding. Getting this feedback early in the process will prevent you from undoing work later on.
Of course, the design phase isn’t the only stage of product development. Integrating user-centered design principles throughout the development cycle will ensure that you consistently adhere to the design process.
Finally, adopting an iterative design process will give you the flexibility to make critical changes to improve your users' experience. A more linear process can lead to more difficult-to-undo issues.
There are plenty of great examples of user-centered design in today's world. Apple products and software are infamously great at implementing user-centered design principles, as are services like Duolingo and Spotify.