Small lifestyle changes have the biggest impact?

Start your day by drinking 1 glass of cold water - This increases your metabolism rate.

Drink a glass of lemon+honey+water. Gives a glow to your skin.

Meditate: Deep breathe in, deep breathe out. This increases the oxygen flow inside your body. Cells thrive in oxygenated environment. It's pretty rare, that you get a chance to deep breathe during your busy day. Hence dedicate some time to exclusively do this.

Sweat a little, everyday. Run, walk fast, climb up the stairs - just move !

Eat at least one fruit a day and some greens. Staying healthy starts at your kitchen.

Use stairs instead of elevators.

In your office, use the farthest restroom from your cubicle. My office is in the first floor, I often climb up to the third floor to use the restroom.

Drink water often.

Read a little everyday - For some reason, it helps me talk better, ideas flow better, makes me listen to others analytically and reply meaningfully. I was not an avid reader until recently.

Write a little every week - it's a practice for the brain to think clearly and communicate your thoughts flawlessly. you kind of train the brain on how to think.