As a great practical guide to reading and applying body language, I'd recommend "What everybody is saying" by Dave Navarro. Guy used to do body language analysis for the FBI afaik, and then wrote a book about it.

http://www.amazon.com/What-Every-BODY-Saying-Speed-Reading/d...

Concerning the body language tips the article recomends, I think everyone except arms crossed behind head is covered for in the book. Arm akimbo, crossed legs, etc.

As a personal tip, I'd give the thumbs up. No, like actually stretch your thumbs out when you walk around or talk to people, and leave them out of your pockets. It's ok to put the rest of the hand in, but the thumbs stay out.

Ahh, and if you're arguing, even if you want to, don't start undressing yourself, no matter how angry you are. 2 people arguing and taking jackets and shirts off usually means business you don't want to be part of neccesairily.