I love it that you asked this question! So many folks will never take responsibility for thier choices and you have it just right
There are many little things we can all do to improve our overall health that requires very little effort. Here are a few suggestions from a retired RN, Mom and Grandmother who at 51 has dealt with two types of cancer and fibromyalgia bad enough to hospitalize me several times but now I am back showing my dogs , training and enjoying the pack, playing with and raising 5 of my 10 grandchildren and traveling a great deal!
Eliminate caffiene when ever possible. It is a harsh habit and more of a drain than a boost. If you must have caffiene get it from Tea. Black tea is beneficial in so many ways , and green tea well there are a million reasons to learn to drink and enjoy it !
Learn to drink water, it is one of the best and easiest tricks in the world. Add slices of lemon, lime. orange or even strawberries and kiwi. You can slice them and keep them in your fridge and tossing a slice or two in your water makes it more interesting and slowly adds small amounts of fruits... and if you cut enough you can munch a slice or two each time you pour your self a glass of water.
Limit alcohol to a glass or two, wine is best but beer is okay too. It has both therapuetic and nutritional effects ! Red wines are brilliant for woman, and if you aren't a big wine drinkeer simply make it a spritzer by adding sprite or 7up.
Limit your salt! We consume so much sodium we cause ourselves huge problems. try salt alternatives, lemon juice and vinegar rather than the salt shaker. As much as I love a margarita I had to learn to really limit myself and pass on the salt. It makes you retain water in obvious ways but also causes problems you can't even see... think high blood pressure,
Avoid artificial sweeteners if possible. Diet drinks are actually hard on your system and new studies show they interfere with weight loss and maint. Real sugar is only 16 calories per tsp.
Add grains. You can boost your grain intake by switching to whole wheat breads and pastas , eat more whole rice, brown rice , wild rice 
Eat breakfast. I hate breakfast to be honest but when I make myself eat it my day is more energized and balanced. A smoothie if nothing else will tune up your day and start you out right!
Do not eat late. I know as a a teen and even in my 20s I thought only old fogies ate early but when my shcdule changed at the hospital I found eating early kept me up and energetice, eating late made me lethargic and feeling bloated.
Eat lighter meals more often, 6 small meals is far better for you than one heavy one.
Meditate, write in a journal , do yoga, Tai Chi, bonsai trees anything that gives you a few minutes a day in your own head quietly and calmly. When you are calm in your mind your health is better.
Eliminate clutter. ( My biggest problem ! I am a pack rat)
Get a hobby, something that shows a result for effort given. You will find a wonderful mental lift for the simple accomplishment and that mental lift improves your health .
Hydrate not just your inside but your outside as well. I rarely wear makeup, but my skin is still in great shape. If your skin is dry or stressed by environment you feel a bit rougher about everything every time you rub your arm or look in a mirror.
Quality sleep over quantity. Too much sleep can be as draining as too little, a power nap is far better for you than 8-9 hours straight.
And one of the most important tips learn to defeat stress by knowing what you can change and what you can't, seems silly but we ruin our health by thinking we have more control over every little nuance in our world. We don't.... learn sometimes you just have to give it up to a higher power and wait and see the results.
hope you find one or two things that may help you a bit and congrats for wanting to treat yourself better !!
Bonita of Bwana