I’ve studied body language and facial expressions for years. Cosmopolitan magazine has a great, easy Body Language Decoder on their web site. Here’s a tip they give in their first meeting sections.

He positions his chest and shoulders toward you, even though he may be looking at something else. Whether it’s you your best friend, or the keg in the corner, whatever a boy aims his upper body at is the most meaningful thing in the room to him. So, if one night a tasty man-morsel approaches your posse, you and your friends won’t need to fight for the fella’s affections; study his body language and you’ll already know who he’s after.