Using a standing desk is huge. If you don't have one, get up at 15 minute intervals and stretch out quickly. It'll help move some blood, improve your performance, and keep you back from getting cranky.
Keep Lots of Water By Your Side
This serves the dual purpose of keeping you hydrated (which is an excellent thing) and also keeping your bladder busy, which helps you remember to get up and walk more often (to and from the restroom).
Batch Cook and Bring Your Lunch
Making a healthy dinner is awesome! Making more to have a healthy lunch the following day is wise. This way the pizza parties and random goodies don't pull you down. You've got your good food and can happily make a better lunch decision without panicking once you've realized you're starving.
Get Some Natural Light
If you can't be next to a window, get yourself some full spectrum light bulbs for your work station. These can boost your mood, energy, and overall performance. They help the day flow much smoother. Taking walks during breaks around the block can also really help you with mood and energy. Get some sun!
Take a Few Breaths Regularly
Pushing back to take a few breaths is an amazing practice. Gaining some clarity really helps us make better decisions and studies show that a few deep breaths to your lower abdomen can reduce cortisol levels and help manage blood sugar better. Stress leads to 90% of chronic diseases so learning to combat it with meditation, yoga, or just some quiet breathing can go a long way towards keeping you happy and sane.