Make sure someone knows where you are and when you plan to come back.
Depending on the field site, you may want to bring a buddy for safety.
Bring your phone, make sure it’s charged
Be aware of your surroundings
Be courteous of others using public spaces -- don’t block paths with your gear, stay out of people’s way, etc.
Carry a mask with you, and wear it if you encounter other people
Wear appropriate clothing -- long pants will protect your legs from scratches and insects. Athletic shoes or hiking shoes will protect your feet from injury.
Wear insecticide
Wear sunscreen
Bring water and a snack
Bring your field book, a pencil, and a couple backup pencils. (a clipboard can also be helpful)
When you get home, check for ticks