I have extensive knowledge of design and code. I'm fluent in Swift and Javascript (NodeJS, React) which means that I can work closer with developers than the average designer. Often I'll create a design system in Sketch or Figma and then create a matching system in code for developers to use. This makes creating future features super easy and fast. No more sitting next to a developer and pixel pushing.
Identify and clearly outline the specific user needs you are trying to address. Then, write clear key performance indicators that will help direct you to create a product that supplies those needs. This will help you ensure that what you are designing and building has purpose and is the correct thing to spend your time on.
Design and code the product in a lean and strong way. This product will change greatly as you move forward and iterate, so at this stage create something that is strong enough to allow you to learn from it whilst also being flexible enough to allow you to chop and change it at speed.
Release your product as early as possible and start gathering data on how your users use it. Do this via quantifiable data that is gathered via analytics tools and also through qualitative data that is gathered through speaking directly with your users as frequently as possible.
Using the data gathered update your product and release the updates as quickly as possible. The more proactively you can react to your customers needs the more positive their perception will be of your product and also the more quickly your product will become exactly what your users need.