Over the course of my life, I have done really well with creating new habits. While I didn't realize it at the time, I did this by identifying the kind of person I wanted to be and then did behaviors that matched that.
For example, while the language is dated, when I was a young adolescent I decided I would be “thin and in shape” and then shifted my behavior to match that (e.g., was active, ate relatively healthy foods, ate less junk food, drank water). It turns out, it worked!
While “thin and in shape” has shifted over the past 36 years to “healthy, fit, and strong”, this identity or way of being in the world has helped me shape the choices I make more easily.
James Clear talks about this as a first step in behavior change. That is, identifying who and how you want to be in the world and then getting clear on what those kinds of people do and starting to build those habits. He of course shares more on how to build those...