As a Road Warrior / Field-based worker, what's your favorite tips, tricks or items? What would you suggest a new road warrior to get or know?

Always carry a basic tool kit and any additional job or site specific items/things you don’t think you will need. Because if you don’t have them that’s when you will need them.

Keep a overnight bag with a change of clothes, deodorant, and socks.
Get a battery booster/jumpstart kit
Keep spare phone charger cables
Keep a bag with bottled water and granola bar/non perishable snacks Get a travel trashbin with bags
A pack of wet wipes/dude wipes
Febreze

Do everything possible to avoid checking a bag.

Don't push your fellow Road Warriors off the Titantron

If you have a set route that you repeat and have a choice in the matter stay at the same handful of hotels.