A human being could be modeled as a self-updating control system that continuously models reality, assigns value, predicts outcomes, selects actions, observes outcomes, and updates the model. Within each of us there is an internal weighting system that defines what captures our attention, what we identify with, and what we perceive as possible or out of reach. What you notice, think, feel, and even what you immediately do after reading these words are shaped by your current weighting system.
Weights change through experience, but only some experience actually moves them. What drives the update is the gap between what you predicted and what you felt, and action produces that gap most directly. Simply knowing this does not make the process easier, because knowing produces no gap. The system changes only when experience gives it evidence a prediction couldn't.
So the practical question becomes: What needs to become more salient, less salient, more rewarding, less threatening, or more central to identity for the desired behavior to become natural? And what is the smallest action that would make me feel that shift right now?