Most of my best new clients have been referrals who were behind schedule at the time and had a freelancer that who had been unable to get the job done so far.
I all cases, I either met their current deadline or missed it by a week, and earned a longterm client who always gives me his projects. In fact I will have to hire someone this year and probably use the services of a freelancer.
Last year I officially decided to cease actively seeking clients.
I totally agree. The easiest way I found to get into this was to first do an incredible job as an employee at every company I worked for. This builds up your reputation. I tended to jump around to different jobs a bit. Usually, when I got bored, I'd move on...but I always made it a point to leave a job with nothing but a positive effect (i.e. they were sad to see me go). After some number of years, other people from those companies may have moved on as well. Keep in touch with all of them (e.g. linkedin). This is how I got my first consulting contract. All my business has been via word of mouth, but I built that network while I was working full-time for various companies. Keep that network growing -- and always do an incredible job, and you should have a good time of it.
Sometimes, though, there is a conflict of interest for the client. In case the job is ongoing (continuous maintenance, new features) the client might be afraid that you will not have enough time to devote for them if they find you other customers, (I'm almost sure that this is the case with my current (only) customer).
