Don't get drunk. This one comes up a lot, really. Where there are editors, there tends to be free booze in almost unlimited amounts. And anything you do not only can be held against you, but tends to show up on film, and in conversation between other editors and writers forever after. Don't talk business .
Business time is for business.
It's why you get to deduct your phone calls to New York. Hanging out is for fun, and editors like to have fun, too. And you still get to deduct hanging out, because you are Networking and developing Meaningful Relationships with Colleagues. I got to deduct the balloon fight at the SFWA party, as well as the rest of that glorious trip. Granted I sold three books that weekend, but even if I hadn't, I met some wonderful people, and still work with many of them.