Well I have a real problem with this, however I have an idea that might help us come up with a good method. Let's reverse the situation: How could a friendly person approach YOU and several imagenary friends, and get to know you? Looking back on my life I have seen only two real ways.
Scenario 1:
The person comes right up to you, excuses themselves, and asks for something such as the time, a cigarette, directions, and so forth. They then follow this up with a question if you continue to pay them attention: "So, do you work down the hall?". And the conversation is on!
Scenario 2:
The person walks by you slowly and at a strategic moment makes eye-contact. If you notice them and make eye contact they stop and smile, and ask a question or make a grabbing statement that's relevant to the situation. For example, if you are at a football event they might say, "Man the game is going great for the Rams, huh?", or if you are at a bar, they may say "Hey, that's a cool hat, where'd you get it?". Ive experienced that one frequently. If at work they may say.."Hey, I think you work down the hall from me, what's your name?".
As far as I can tell, just being friendly is a no-brainer and totally normal for other people, but it scares the shit out of us because of our anxious fantasies. I haven't been brave enough to try this out much, but when I am drunk, high-on-success, or feeling great, I will occasionally become extrovert.
Hope this helps.