Have you got a product idea? If so then start building something right-away and talking to people about it -- promote it, attend barcamps, democamps, etc.. Eventually you will find someone who believes in it and will want to work with you on it and refine it, i.e. a co-founder.

My present founding team consists of people I knew, trusted and was friends with prior to starting work on my product. But they did not start working with me at the same time I started out.