Finding startups for work in San Francisco?

I recently started looking for new opportunities in SF, and seemingly by chance began talking to a couple of startups. The idea of helping these companies grow is really exciting, so I've been trying to find other startups to talk to. Unfortunately, my network in the bay area is not that large, so I'm unsure how else to find them.

So, what are some ways that I can find startups that are hiring and might be interesting to me?