Being a good *human centered designer is a lifelong pursuit of understanding how humans operate. Two questions to fuel this pursuit – (1) What does it mean to be human? (2) How do humans make sense of the world?
To get started, introduce yourself to the field of epistemology, and read this book. If you want to dive deeper into the intersection of epistemology and creativity, follow up 'Little Manual' with this series of brilliant essays by Bruce Voljak.
Adjacently, or as you begin answering the second question, I would begin studying these fields of thought:
- Critical Theory
- Embodied Cognition
- Human evolution and technology
Two of the most prolific design theory books I've read in recent years are Design for Dasein and Design: Invention of Desire. Both of these books will be much richer if you've primed yourself on the fields of study above.
Finally, pursue beauty and inspiration. Do things for no reason other than the pure pleasure of them. Note what you find interesting in the world. Be curious, and even better, be curious about your curiosity. Practice observation like you would practice a sport. Ask lots of questions.