I've been having to turn down work. For a while I was able to schedule it for later times as it comes in, but once I have at least 3 months booked into the future, I won't take on any more. A fair amount is ongoing work acting as a part-time dev on a project. I don't do much in the way of short "build me a website" projects

Also want to say that as valuable or even more than building referrals through clients you've worked for is building up a network of other dev contractors you've worked with. Much of my work is a job someone else lands and then needs to bring in additional help, or a job they turn down for lack of availability. And likewise, I do the same for others I know.