I've written/cowritten 3 books and a whole lot of articles over the past ~15 years on a freelance basis. Most of the good work came through an agency, StudioB, though I had pitched magazines and other places from time to time on my own.

My experience is that a lot of the good sources of ad-hoc work have dried up. That's not to say there is nothing now, but it's not the shooting-fish-in-a-barrel it was a few years ago. The demand has gone up and down over the years so I'm sure it'll be back.

As you've seen it's a lot of fun. I always treated it as a way to get other people to pay for me to learn the stuff I would normally have done in my spare time anyway. The money was good for the time invested, but I make far more just working a day job.

If I wanted to make an income from it, I'd be finding a company or two to attach myself to rather than piecework.

I've found that the industry is very focused on your portfolio, so continue to build upon that.

Also, be very nice to the editors you work with. They provide a lot of feedback to the people making the decisions, and no one likes a prima donna.