I now have 433 days worth of data about my sleep. Although some of it is a bit subjective, I think it's good enough to give me an idea and a whole lot better than the guesswork I was using before. It seems to be enough that some noticeable correlations are forming.
In order to be sure I'm not looking at noise and that I'm focussing on the most important things which affect my sleep, I'm only going to look at the most significant factors.
The correlations are against "missed sleep" which I defined before, so negative correlations show things which are good for my sleep.
The following were good for my sleep:
The following seemed to have a bad effect on my sleep, though as you can see from the numbers, not very strongly:
The following seemed to have no significant effect either way: Daylight hours, ZMA, Evening meal size, Worry, Screen after 6pm. For me that's enough to encourage me to make the following lifestyle changes in the hope of better sleep. I think this will be more personalised and useful to me than generic sleep hygiene.