Ask HN: If you've successfully outsourced software dev work, how did you do it?

I've tried outsourcing work in a variety of ways on dozens of occasions over the past decade. I've worked with local developers and foreign coders using outsourcing websites. I've created detailed specs, chosen virtual coders with good reputations, or local firms that come from a recommendation. And yet the vast majority of these projects have failed.

Local development firms have gotten the project to 95% done then failed to eliminate crucial bugs, or else done the low hanging fruit and pocketed the deposit (I'm willing to name names here).

Outsourced developers have treated me like their personal QA worker, required dozens of reminders to get their work done, or ignored key parts of the spec (in the most recent case I listed two bullet points under the heading "Important", the coder turned in "finished" code that failed point 1).

For those who have successfully outsourced, what was your secret?