Celebration usually needs a second person. Someone has to notice, which is the part outside your control, and on most days nobody does — the thing you quietly fixed, the difficult email you sent well, the hour you didn't waste.
So the daily version has to be smaller and self-administered. Not a party. Closer to an acknowledgment: that was hard and I did it.
Say it internally at the end of something today. It looks thin written down and works better than it should. Plenty of people go entire years without saying anything of the kind to themselves once.