Reading Design of Everyday Things by Don Norman is a great start.
There is a whole track on design at Coursera, but I only watched one course from it, so can't say anything about its quality.
It seems the term "design thinking" has been hijacked by consultants. What I mean by it: being aware of how tools/artifacts drives people's actions/behaviors and changing the former to proactively make people's lives better. Sounds simple, but in practice today's world is obsessed with needs, wants and features, not the actual process of living with technology and other human artifacts.
There are many books talking about UX/UI design, but most of them are quite abstract and do not tell you, when exactly, on which stage of your software development process to apply the knowledge they present. This often leads to a typical mistake done by developers, that I've seen in too many projects, when UI design is considered at later stages of the project, when they are starting coding the UI and all the backend is already done. Because of that, the process is equally important and needs some of your attention.
To achieve really good results in UX design, to do it at the right time, I'd recommend to start not from the books, but from the interaction design specialization on Coursera at https://en.coursera.org/specializations/interaction-design or you can take just intro - https://en.coursera.org/learn/human-computer-interaction . You can take the courses for free and they'll give you the necessary mindset and understanding of process. You'll find that product design actually starts from UX, not ends with it and it defines the necessary requirements framework for the system architecture, which you can use later in combination with BDD/DDD. After that course you can start reading the books (Steve Krug, Don Norman, Alan Cooper, indeed!) and platform guidelines (my favorites are for Google Material Design and Microsoft's Modern UI).
It will be great if someone here recommends some books or articles about UX design process and integration of it into popular agile methodologies.
Earlier this year I did the Stanford Introduction to Mathematical Thinking course on Coursera . I found it fairly challenging but managed to finish with a distinction. The instructor was particularly good.
I'm now working through UCSD Interaction Design specialisation , which is a series of courses followed by a project. So far its been very good, although the short course format (3-4 weeks) means that there isn't time for much of a community to form among the participants. I've learned a lot though.
I'd recommend both courses.
I did #27 "Introduction to Mathematical Thinking" during Feb-April this year. I enjoyed it a lot and found it challenging without being impossible to complete. Finished with a distinction and a feeling of great satisfaction.
I'm now doing Coursera's Interaction Design specialisation , which is proving to be very informative and a lot of fun.
If you're considering doing a MOOC then I'd definitely recommend it. Choose a free, short-ish course to start with, make the commitment, and dive in.