Honestly, networking has worked best for me. I've met a lot of clients and business partners by getting involved with online forums frequented by my target market and offering helpful advice and encouraging words. Sometimes just posting, which gets your signature line (which should contain your biz name and a link to your website) out there for potential clients to see, is enough. Also make sure you have a profile on as the forums you frequent and any other free directories you can find; this move has resulted in several people contacting me just within the past few weeks.
As far as face-t-face networking, this doesn't necessarily have to end with business networking events. Just talking to people in everyday situations about what you do can lead to valuable business. For example, I was telling a friend of mine all about my business a few months back (with the hope of convincing her to give virtual assistance a shot, I must admit

) and she ended up handing off one of the business cards I gave her to one of her coworkers, the head of a division in her company who needed copywriting assistance. He has been an unbelievable source of ongoing business for me. And just last night, I met a group of old friends for dinner, and I got to talking to a friend of a friend who happens to own a local small business. We started talking about what she does and what I do and how I might be able to help her down the road. I gave her a business card and voila - potential client, right where I least expected it.
The moral of the story is that if you keep your eyes open, you can find opportunities on the street, in a restaurant, even at a friend's home.