I used to wait for a fresh start on a Monday. Now I just pick one small thing and do it today, because small things are the only ones that stick.
A glass of water before coffee. Ten minutes outside before the phone comes out. A bowl of something colourful for breakfast. None of it is dramatic, and that is the point.
The habit that surprised me most was a short evening walk. It clears my head, and I sleep better when I have been out of the house, even for a few minutes.
Choose one habit this week and keep it embarrassingly small. You can always add another next week.