There's only one of these Good Things I regret never having succeeded at starting, and that's journaling. As I'm getting older, I realize there are more and more years during which I've been alive and it's getting harder to look back at them and make sense of them, or remember when a particular thing happened. I'm 45 now, which really isn't that old, but also not that young anymore. When I was younger, say 25, I had 5 years of (somewhat) adult life behind me, and they formed a relatively coherent and linear story. I now look back at 25 years of being an adult, and that story is now five times as long, way less coherent, and no longer linear, so remembering it all is becoming almost impossible. But the longer I live, the more often I find myself wanting to remember when a certain thing happened, or what my state of mind was at a certain point. I also have a wife and have three kids, so those add more stories to remember (or more characters in my own story).
I've been thinking of catching up. To start an Excel sheet, with years in the left column, and then start filling in events that I can remember or verify with certainty (marriage, births of kids, buying the house, jobs, projects, travels). Hopefully this would trigger more and more memories that I can then fit into that context, until I get to a somewhat complete and coherent story of what's been going on until now.
I think this might also make starting journaling easier because I would be continuing a story, instead of starting to write one at a random point in time.