Repetition and consistency

Do it every time you remember and don't torture yourself if you forget. Force yourself at first and set up reminders, post-it notes, alarms, whatever.

At first you'll be annoyed, you may even feel dumb but after a month or two it will become habit and you'll forget less and less .... after a few more months it will become automatic.... after a few years you'll become so attached to whatever it is you'll feel strange not doing it.

It's how I maintained daily journal writing for so many years. Don't get me wrong, years ago I was sporadic and did an entry once a week, sometimes once a month or skipped an entire summer but now I do it every day. Some days my entries are long, some days I only write a sentence or two but I always get myself to record something every time.

Now I feel strange when I don't fill in my daily writeup.

Sounds like it wasn’t all that important then