When starting a new habit, it is fundamental to make things as easy as possible by removing any friction, creating systems, and modifying your surroundings to make the habitual action as easy as possible.
For example, when building my running habit last year, putting on my shoes and going out the door wasn't easy. So, following expert advice, I started leaving my shoes close to the door and preparing my running gear the night before.
Also, being strict with time and specific with the objective makes building a habit much easier. In the beginning, I focused on running 5 times a week, at least 2 miles, and always first thing in the morning.
But once the habit is built, once the routine becomes almost second nature, we can relax the constraints.
The point of building good habits is to turn them into practices and not routines.
Routines are habits that anchor themselves to a particular point of the day. Routines are fragile because they depend on the point in time and context.
So, the point of habits should be to turn them into practices. Practices differ from habits and routines in that they are part of our identity.
Running is now part of my personality. I don't care about the distance nor the time of day I go out. I focus on enjoying every single step.
As Ryan Holiday says, routines are about daily rhythms; practices are a lifelong pursuit.
So start with habits but aim for practices.