How to "Swim" in the Sea of Strangers

Now that I have systematically studied how to swim the crawl and have made fairly substantial progress in it, I have to study how to "swim" in the sea of strangers, too, though I do not know how. By "'swimming' in the sea of strangers" I mean socializing in a context where I do not know anyone personally in advance. Synagogues and health clubs are examples of such a context.

I was born and brought up in a place where everyone knows everyone else. So throughout my elementary and junior high school days I had no opportunity to acquire the skills of "swimming" in the sea of strangers. The crucial step is the first step of greeting someone who has stopped being a total stranger and has become a known stranger. Unfortunately, I have not learned this important skill either as other people generally approached me after I did something good or special in certain areas.

A synagogue can be a problem in this respect, as I cannot excel in any activity there. I visited Ohel Shelomo Synagogue in Kobe for seven years, but it took me a long time to start talking with enough people visiting there. In Chorev Synagogue in Jerusalem, where I have been davening for the past several years, I have made friends with a number of people, but mainly because they started speaking to me first. There are many people there who still remain known strangers because neither I nor they greet the other. Incidentally, on the basis of my experiences in these two synagogues (and other places) I have to say that sabras are generally far more closed than they think they are.

Another problematic place is the park where I have been running on every weekday for the past several years. I can already recognize quite a few people who run at the same time when I run. There is at least one excellent runner I would like to get acquainted with, but even the mere thought of just saying hello makes me quite nervous. I do know that there is nothing to lose if I say hello and receive no answer, but I find it very difficult to do so. It is ridiculous that at this age of mine I still have such a difficulty socializing with strangers.