I keep talking about the Lean UX Methodology. Here is an introduction to it from the Interation Design Foundation.

Lean UX is an incredibly useful technique when working on projects where the Agile development method is used. Traditional UX techniques often don’t work when development is conducted in rapid bursts – there’s not enough time to deliver UX in the same way. Fundamentally Lean UX and other forms of UX all have the same goal in mind; delivering a great user experience it’s just that the way you work on a project is slightly different. So let’s take a look at how that might work.

https://www.interaction-design.org/literature/article/a-simple-introduction-to-lean-ux