So just to go a little bit more in depth with my answers:-
Exercise - is sometimes no more than a walk or gardening. I have a bike and used to commute to work by bike (3.5 miles) currently have a knee injury and am not cycling but hope to do so next week. So I ensure that I do something with intention every day. Stretches/sun salutations in the morning, a walk in the green (park or countryside) a cycle, some yoga or a swim. It doesn't matter what it is, it's an intentional move your body time.
Food - Fresh food is key - eat something vegetable and in season daily, add green stuff to sandwiches, fruit on porridge, grains in porridge, make my own cake to eat (helps cut down the quantity lolz) make my own jam/marmalade and fruit curd, mostly cook from scratch, chose complex grains and carbs (except pasta, love white pasta so now do the 1/2 and 1/2 seeds of change type) try and shop local produce and grow some myself.
Sleep - all those boring things like going to bed at a reasonable regular hour (I get up early to finish stuff as I find I am quicker in the mornings) Screen time is minimal after 8pm. Phone is never in the bedroom. Do not disturb goes on at 8pm. Caffeine in the morning only. Sugar avoided except for mealtimes - no late night snacking. Outside daytime walks/exercise really important to sleep, too. Not stressing when waking up - I have some bluetooth headband headphones that I listen to podcasts on if I'm awake in the middle of the night.
Those three pillars of self care help me cope mentally with all sorts of stuff.
Remember don't sweat the small stuff, implement change gradually - pick one habit that would make a big difference and stick with it. When you're happy with the habit pick another one. Don't set yourself up for failure - chose things that you can realistically do and tell everyone (friends and family) what you're doing - you are more likely to stick with it
Hope this helps