Write a good all-around job application and a short CV and go on a part-time job searching spree! That's the first thing you could do, and I'd also recommend what Glori305 said: Put up a poster or two at your local shopping places with a "hey, I'm this-and-this old and would like to babysit your children. I work for this-and-this wage, and are free at this-and-this time"... It's worked really well for those of my friends who've done that (:
I made more money babysitting kids than I made at my first job, on a per hour basis.
It is not steady or predictable work, but now is a great season to get into it, as lots of people need babysitters for holiday stuff, and so their "regular" babysitter is probably going to be very busy.
Just put fliers up in the local grocery store etc.