The best thing you can do for your body is to get proper rest 7 to 8 hrs. The number 2 thing is to drink more water at least a half gal per day. Stay away from drinking well water, alot of nasties in there. Mainly chemicals. I use bottled water.
When it comes to food. Try to use less processed foods. There are dyes salts and sugars in them. Atound 1906 doctors noticed an uptick in colon problems that didn't exist before. Processed foods were introduced about 10 years prior. Buying raw veg and fruits and meat is the healthiest way to go.
Sugary soda and diet drinks are no good. Artificial sugars just as bad as as sugar. I use stevia instead but not alot. They put sugar in everything even barbecue sauce. Sugary cereals keep to a minimum. Fried foods like French fries and anything fried is bad for the body, as years go by it wears on the body in illnesses. Excess alcohol is no good either. It puts you in a hole one way or another and takes many years to undo the damage. You can do a u turn at any time and try to right the ship (your body).
Exercise every day. Park your car far from the entrance so you can get in some more steps. Work with dumbells for 5 min in the morning. You only need 1 dumbell to get started. Use a 2 or 3 pound dumbell. Turn your hand palm up and lift the dumbell bend your elbow toward your body, do this 5 or 10 or more times. Switch to the other hand and repeat. Thats 1 set. Set 2 repeat set 1. After a month go up in weight say 5 lbs more. Within 6 mos your arms will be stronger and have more definition. 5 min a day you will see how it benefits you within a month.
Breathing exercises. Sit in a chair, look forward breathe in through your nose deep. Hold breath for as long as you can, then slowly blow out your mouth. Do this 20 times per day. You are getting more oxygen into those lungs. Do this in the morning.
Finally focus on what you want in your life and do 1 thing today to get you closer to your goal. Write it down in your book or journal.