Speaking from my experience, body language may help a lot when talking to people.
Most of what I will tell you, I have read it (and practiced it) in diverse books and a recommended one would be “ What Everybody is Saying “ by Joe Navarro.
Most of my experience is rather related to talks with strangers in libraries or at conferences
Personally, I am a very shy person but on such occasions, I try to hide it by assuming a very “open” posture. Usually, a shy (reserved person) would try to minimize their stance by keeping their hands in the pockets and curl the shoulders in a shell-like posture. This is clearly a sign of a person who wants to keep a low profile and does not want to be engaged with anybody else. An open stance, on the other hand, shows confidence (and in some instances, a sense of authority). So, upon addressing a stranger I always keep my hands out of the pocket and clearly visible (which as you know back in the Medieval age was also a sign that a person was holding no weapons and so was not a threat).
At this point, the first thing I do is usually make eye contact.
Now, this point is also important.
There are some signs that are also indicative of the other person's reactions:
- Eye movement: you can see if the person likes you (or appreciate you coming closer) by the way the eyes move. Eyes, well open and eyebrows lifting up indicate a “pleasant” surprise, interest. While eyes getting narrow or even “blinking” is more a sign of discomfort (“who the hell is this person?”). This helped me in some instances to decide whether or not to pursue my “approach”.
- Posture: this is easy. If the person notices you and turns in another direction there is a clear sign they don't want anything to do with you.
If I can pass this first filter then my next move is to introduce myself.
I do not see the point to start a conversation with a stranger. So, I would at least tell my name to start making it personal. Also, a name tells already something regarding your country of origin (or at least the influences).
As already said by others, I won’t ever approach somebody without nothing to say.
So, introduction and then get right on the point. The person has to know that there is a reason why you approached him/ her: are you working on the same topic? Are you reading a similar book? Did you notice her/ him having trouble with something?
Once that the conversation starts, look for signs that tell you when the conversation should be over:
- Is the person checking their watch?
- Is the person looking around (maybe for someone he/ she is waiting for)?
- Is the person pointing with part of the body (usually the feet) somewhere else?
If I notice such behavior, I would usually ask if the person has time constraints and whether it would be possible to continue the conversation via email or telephone.
Forcing a conversation is never an option. Better to say a few lines and then have the chance to continue later than start talking random topics (the weather, your CD collection, the awful flight you had on your way to the conference… ) in order to get the conversation going. Live to fight another day.