I was more going for advice, and whereas I would love tips on talking to individual people, the goal here is to find a way to better talk to everyone. For the past few days, this is how my conversations break down. (Disregarding here, of course.)
Time spent with friends: ~75% of my day.
Participation: High. Equal to or above the median talkativeness of the group.
Time spent amongst strangers: ~25% of my day.
Participation: Low. My talkativeness is less than half of the median.
Talking to people about what we have in common sounds like a good plan, and it'll likely help me at my high school where everybody has a general idea who everyone else is. Outside of that though, I don't know many people, so I don't know what we have in common.
I suppose what I'm really trying to do is be more outgoing, but if it were as easy as saying that there wouldn't be a thread, I suppose.
Why are you talking to strangers? Unless you like passing conversations, strangers tend to keep to themselves when out doing non-recreational stuff.
It may be worth reading a conversation book, and I'd recommend it, as I went through that phase for a year or so. It turned out I was picking conversations for the wrong reasons. Nowadays, unless I want to get to know someone better or if I have some reason to talk to them, I'd just make non-followup chatter.
Here's some ideas. The person sitting or standing next to you on the bus? Idle chatter may be useful, but there's little chance for follow-up unless you like the idea of being 'busbuddies'. People on your track team? It's certainly worth getting to know them, and if something sparks naturally there could be some non-track follow-up. Even then, there's the 'trackbuddies' path, which could be okay if you guys run often.
I don't know if this applies, but for some reason people think intimate relations are completely separate from friendship ones. They start up the same. If there's no friendship spark, there's no intimate spark.
If people don't talk to you, then there's many reasons why, but if you can tell why, it saves you the effort of wasting time putting forth, uh, effort. Say you're at a party. If you put on the sour puss, people won't be inclined to talk to you, and some may ask what's wrong as a token participation effort. If others are donning the sour puss, they may not be enjoying the party, may not be getting enough attention, or may have outside influences affecting their atmosphere. Anyone seem worth dealing with? Yes? Great, potential fun party. Say hi, see if they're responsive, and join a group conversation. If they remain responsive, talk to them separately some time later. Congrats, you may have a 'same-group-of-people-party-person'. This person may evolve into something better, like a one-on-one friend or group activity friend. You get the idea, friendships and relationships come in waves. The more time you have to interact, the better you can judge how they can be of use to you, as compared to hoping the best from strangers.
Any questions? I can gear more towards your original question.