What a great thread!
My habits are mainly work related but I have carried them over into home too. Around 5/6 years ago I was really unhappy at work, and started listening to the audiobook of ‘The Happiness Project’ on my drive to and from work (still listen to the podcast on occasion).
Two strategies she suggested that I consistently use at work are the power hour - prioritising all the little tasks that can be accomplished quickly, and dedicating an hour to them. I do this once a week and it has transformed my life at work. I pick an hour each week and dedicate time to all my little jobs (I am a teacher so can’t often use my time like this).
I also spend some time at home in the early evening (not really an hour, just 30mins or so) before DD goes to bed going around the house picking up all the bits and bobs that are in the wrong place or need tidied away and put them back in the right place. Sounds silly but means everything is all tidy before DH and I have dinner so we can get on with our evenings without having to do any tidying up.
The other thing I took from THP was a kind of mantra ‘be kind to your future self’. Essentially I try to make my own life easier for tomorrow - so, I always write my list of priorities for work for the next day before I leave for the day, make sure little bits and bobs that shouldn’t really be left are done, do boring tasks properly to avoid having to redo them (mainly dull admin tasks!).
I like lists and control and have realised during lockdown while at home more that lacking these routines are causing me a bit of stress.
I have read all the other posts with great interest, I am not so good at carrying over habits to my own actions/behaviours at home so I would like to put some of the ideas into practice, especially about drinking less Diet Coke and snacking! 
Fab thread, thanks OP!