How do freelance software developers get clients

Hey everyone. My name is Ken and I'm interested in becomming a freelance software developer. Forget the tech details for now.

Can you please let me know how you get clients? Do you use online sites like oDesk or eLance? Do you contribute to open source projects? Do you network with local businesses?

Any advice for an aspiring freelance developer would be very welcome..

Thanks in advance.