Don't act like a total douche, no matter the topic. Respect others opinions. Use dry humor sparingly. Etc.
Sometimes acting like a douche can be the only option to your desperate opponent, but if it isn't serious, I wouldn't bother it.
Unless someone proves a point on a topic, you should respect their opinions and negotiate. There are some exceptions though.
Dry humor can be fun here and there, just make sure that other people understand so they can play a long a little, don't make it a serious thing against an individual.