That's the real challenge—moving from academic concepts to everyday design judgment. What helped me was finding a guide that treats psychology as a practical toolkit, not just a list of terms. It breaks down how principles like mental models, Gestalt grouping, and decision-making biases (like loss aversion) directly inform choices about hierarchy, workflow, and microcopy. For a solid, actionable framework that connects the 'why' to the 'how,' I'd recommend this deep dive into psychology UX design.