I’m pretty much a loner, and I don’t get out much. Still, I find it fairly easy to make friends.
First thing is you have to look somewhat approachable. You don’t have to be stylish, but you have to look at least somewhat clean and presentable. Normal hygiene should suffice, provided that you don’t douse yourself with perfume/cologne afterwards. A light scent is OK.
Second, you actually have to make eye contact and maybe signal that you’ve seen someone. When I’m in the waiting room at the doctor’s, I look up at people and maybe nod as they go by if I’m in the mood to talk. Otherwise, I keep my head down. I guess this goes under the approachable heading.
Third, you have to be able to carry on a very light, fluffy conversation. There’s a reason why people talk about the weather, it’s because everyone in the same area is experiencing the same thing. You can gripe about the snow, or comment that you wish that the weather was like this all year round (my favorite comment during early spring and late fall here). This lets the other person make similar meaningless comments. Neither person has to take a stand on anything controversial. You can try out gentle forays into other issues, if you think that you might like to get to know a person better.
Fourth, be able to give out a way that someone can contact you, without giving out too much personal info. Email addresses are PERFECT for this. Don’t give out your main email, give out your secondary email address. Don’t give out your spamcatcher address, because a lot of otherwise fine people just can’t address an email to save their lives…and I always delete stuff in my spamcatcher’s inbox that just says “Hi” as the title.
Fifth, accept the fact that you won’t become bosom buddies with most of the people you talk to. You just won’t click. And that’s OK.
Oh, and if you are approaching, be aware of body language. Some people are ready to be approached, but not so eager that they are approaching. Some people are either in a bad mood or just NEVER want to be approached. For instance, most people seem to hate to have someone ask what they’re reading. Now, personally, I usually enjoy talking about my current read, but it seems that the majority of TMs hate it. So, if someone is reading, or seems pre-occupied, don’t approach them. And if someone seems approachable, but when you talk to them, they give short answers, almost grunts, leave them alone.