Have as big a goal you want.
But take small, effective, laser-focused steps.
Do it daily so become a habit. Plus, it takes about 2 months (it varies between 18 to 254 days) for a habit to kick in. Be discipline enough until the habit to stick so that you can do it without ever thinking it. Call it the auto mode.
What I do is to have a daily tracking sheet on an actual piece of paper. List one habit or one small thing to do each day. Mark on the list every day.
Lesson: Think big, take small steps.