Alex, I suggest you purchase the book "Street Magic" by Jeff Sheridan and Edward Claflin. I think we still have a few copies (it's pretty cheap in softcover).
Do you want to know what Sheridan did (dressed entirely in black, before anyone else decided it was cool) on the street, silently, and drew huge crowds, mesmerized them, in the middle of bustling Central Park in New York City:
1) Card manipulations
2) Sponge Balls
3) Rope magic
Those were the basics of his act.
Many others, like Cellini, focused on more traditional items like cups and balls and fire eating. Cellini is great. Others, like Gazzo, are horrifyingly rude.
You will need to find a character to perform as on the street. You need to figure out how to dress. You need to figure out if you're going to talk or not. Here's a tip: if you decide to bring your close-up magic with you and do tricks like "Triumph," you're already moving down the wrong road. I think silk tricks can work really well if they're done correctly. While it may sound silly to use rainbow colored silks in San Francisco, it's not a joke--it's a great idea if you know that a large percentage of your audience is gay. It shows that you acknowledge that in a "magical" way, and it'll probably get you some contributions. In some sense it's just like working a trade show, except focused groups of individuals are your customers instead of corporate clients.