This thread has inspired me to restart some of the good habits that have fallen by the wayside in recent months.
I am full of bad habits but I'm obsessed by the topic and have read and/or listened to loads of books about habits - Atomic Habits, Tiny Habits, The Power of Habit, Good Habits Bad Habits are just some of them. I've had some success - quit alcohol, more healthy diet, bit more organised but a lot of habits have slipped.
And from all of them I think the most important piece of advice is to start small. Very hard to do that because when you make the decision you are full of motivation and it's hard to keep it small - you want to walk 5 miles instead of one. But slowly building a teensy tiny habit works far better at making a habit stick. So if you try something, and find after a period of time you've given up - try again but scale it back to just a tiny bit - like 2 mins of stretching daily rather than an hour of yoga.
Another tip is triggers - I use my fitbit and have various vibrations throughout the day to remind me to do certain things - tidy my work desk, file a certain report etc - but I find music is a great trigger - I have favourite songs - some of which rotate - which start playing automatically to remind me it's time to tidy my work desk - time to get ready for bed - time to exercise.
And the last tip is - reward yourself. I don't mean with chocolate - but make your own version of a star chart. Sounds silly but they work just as well for adults as they do for kids. Ticking off a habit nightly can be reward in itself but you could also promise yourself a treat like getting nails done after x number of ticks. And don't beat yourself up over missing a day.