I've been looking into vitamins and all that (actually recently changed my major to nutrition!) and the one that would be most helpful to take every day, even if its the only one, would be probiotics. It's great for your body as a whole. They help your digestive system, as well as boost your immune system. I also take a couple multi vitamins every day, as well as a d3. All the other vitamins I take are to target specific things (my main issue is my skin...I have acne, so I take vitamin b5).

As for food, I recently cut down majorly on my sugar intake and it has made me feel pretty good! It's pretty hard to totally cut something out of your diet. I usually have tea at night with sugar...and I do eat carbs, which later turn into sugar, but I just make sure to not have TOO much of all that.

I also try to make my snacks healthy. If I'm craving something midday, I usually make a small salad, or just eat an avacado. Eating lots of greens is also important! Every dinner I eat contains a serving size of meat or fish, and either broccoli or brussel sprouts (a couple times a week I'll add roasted potatoes into the mix).

other than that, I just try to get outside. You can usually get your daily dose of vitamin d by being out in the sun for 15-20 minutes. It's great to exercise, but I'll admit I don't do it every day. I'll walk my dog a bit every day though and get my vitamin d and i'll be good to go!

That's how I usually stay healthy, and it's not too hard!