I am a big believer in small lifestyle changes that give big long-term results.
It is hard for people to sustain massive shocks to their daily routines, unless some stressor triggers it such as moving, changing jobs, etc. Instead, there is much greater success in making minor adjustments. The minor adjustments I prefer are those which take very little time or effort, but can have profound impacts on the quality of our lives. Here are a few of my greatest hits:
Make a habit of choosing mineral water instead of sugary soft drinks.
If you have a time-based routine such as a coke after lunch, switch it for a mineral water.
Best if you drop them altogether and drink only water or unsweetened teas (green tea, oolong, jasmine, etc.) instead. One step at a time.
Maybe for some people this is not a minor change, but if you can switch it to unsweetened tea you are already doing yourself a big favor. Especially bad are the big calorie sugarccinos of the Green Monster. If you need the caffeine (or think you do), see the next item on the list.
Make sure you are getting 7 hours or more every night without fail.
Adjust your schedule so you do. Catching up on weekends is no substitute.
Better if you don't, moderation if you do. Try to avoid beer's big calories, soft drink mixers (like rum and coke), and always always hydrate. Red wine is a good choice if you must.
Try to avoid their high-calorie, preservative-laden meals.
Best is to make your own bento (or kindly ask your partner to help).
Better yet, make your bentos together the night before.
Make at least one meal a day meatless. Breakfast is an easy one, but a big salad dinner is nice, too. Maybe for starters make Monday your "green day". Increase as you see how good you feel.
Get a few minutes at least of sun every day you can.
Needs to be scheduled time for yourself to do any activity you like.
Make sure you are getting at least 3 times a week for at least 30 minutes each.
I stretch before bed. Morning is also nice.
Even though I am a morning shower guy, I still take my Japanese bath soak every night.
Something I just can't live without.
Maybe you already do some of these things. Maybe you can add a few more.
Even doing one new things, and making it into part of your routine with add to the quality of your life and health. One step at a time.