As mentioned, LinkedIn seems to be the prime spot for getting initial work in both employed and contracted work, currently.

Long term, you want to "always be networking", as much work will come from word of mouth. Make sure to be creating contacts and relationships at each job you do get, as you never know who the next lot of work might come from.

I did some contracting for a brief period. My second contract came from the personal assistant of the Managing Director for the first job. We chatted a few times whilst I was working there, and it turned out her husband ran a software firm and was in need of my skill set. My understanding is that this type of situation is not uncommon.