Safety in the field is important enough that I have condensed it into the following points:
Take a partner. Remember there is safety in numbers.
Consider taking a cellular phone so that you call for help.
Consider taking a whistle so that you can draw attention to yourself if necessary.
Avoid going into extremely isolated areas.
Avoid contacting extremely intoxicated subjects and those with extreme mental health problems.
Pay attention to body language. Don’t approach people who have their head down and those who seem to be going out of their way to avoid making eye contact with you.
Be careful not to invade personal space during your contacts. A good rule of thumb is to stay three to five feet away from people.
Stand bladed at 45 degrees with your feet planted shoulder width apart and your knees slightly bent. This should help keep you balanced on your feet and afford you some stability if you need to react quickly or escape.
Make brief eye contact with the people around you (but don’t stare). Let people know that you see them.
Be aware of your surroundings.
Listen to your intuition and move out of the area if you start feeling uncomfortable.