There are apps for habit forming. I use a medication timer app and just never mark that I've done something I haven't done.

I use apps. Habit trackers and Google assistant is great. I cant do planners or writing stuff down. So whenever I remember something to do or buy or whatever. I'll just go ok Google add ....to my shopping list or add this to my calendar or remind me to do this at this time or whatever. It helps me alot or I would forget everything. I've missed classes and calls and other things before I would do this method. Or if your someone who is usually in the kitchen or office and not usually on the phone often, use visual habit trackers with magnets or a dry erase board.