Discipline is less important than motivation, and consistency is more important than habits. That's the whole procedure for altering your life with wise decisions.
After that, you cannot rely on motivation since it comes and goes on a whim; it is merely the starting point! Many people make the mistake of depending just on it and then questioning why they cannot keep on track while others do.
Next, you need discipline: you fill in the spaces between to establish a habit when you commit to something and stick to it even when it's difficult or when you don't feel like it.
And you establish a routine by being constant. Today, tomorrow, again, and once more.
When you remain consistent over several months, over half a year, it becomes a habit; once anything becomes a habit, it is easy to maintain continuing since that is now your default setting. It becomes your new normal, the most straightforward decision you lean back into without even considering it.