Ask HN: How do you find and vet freelancers/contractors?

I've got a couple of side projects that I have built the basics for, but want to take further. I've been reading the book Start Small, Stay Small, and have been pretty heavily influenced by Walling's advice about finding freelancers to quickly build MVPs.

What tips do you have for finding and vetting freelancers for side projects? My idea is to start by distributing small projects among a few freelancers and then see who I like working with most. However, I'd appreciate hearing how other people work with freelancers for side projects.