If you must be late, try not to disturb the class. If you are consistently late, this problem can become an attendance issue. Conduct yourself in a professional manner. Treat all class members with courtesy and respect. Yes, I realize that some of your friends won't recognize you without that ball cap backwards on your head, but that is the rule.
Beverages are okay, but no eating in class.
Do your best work. Our objective is to discover the truth. Toward that end, we make arguments, obtain evidence, draw conclusions, etc. Our concern is with ideas, principles, facts, evidence, etc., not feelings. Such scrutiny, criticism, or rebuttal is always to be directed at the statements someone makes, not at the person who makes them.