Playing a musical instrument, ocarinas are really easy to carry. I have an ocarina and when I got stuck in line, or was just traveling some place by myself, I would just start playing and that would a). let the people I was trying to find be able to find me by sound as well as sight and b). I got pulled over a lot with people being all, "Omg! That's [insert song title here]!" And we'd start talking about music, games, costumes, whatever.
Also, I went to fanime with my family (who live down there), so they knew a lot of people already.
And this may sound silly, but going to other cons work as well, I go to Sacanime and I saw a lot of people I know from Sacanime from Fanime.