Do your homework. Make sure to do some background reading before you attend or depart on a press trip. Know at least the basics about the destination or attraction and compose a few questions to ask of the sponsor.
Act professionally. This should go without saying, but be on your best behavior when on a press trip. You are representing both your company and yourself. That means no loud talking, excessive drinking and wandering away from the group. It also means that you have to attend all of the planned functions, no matter how boring.
Be punctual. Arrive at each function on time. If you are traveling, don't be that person that holds up the bus every morning. Set two alarms if you must, but be punctual.
Within a week of the event, follow-up with the organizer by sending a thank you note. If the function was a lunch, dinner or media tour of an exhibit or attraction, sending an email is fine. If the event was an overnight trip, send a handwritten note.