[fooandbarify]

I've had decent luck on Odesk with Wordpress stuff. (Tangent: I enjoy using Wordpress less every day. It's time for something better.) I only outsource easy/boring work. I found a couple developers for the first job that were good enough for me to continue hiring them for subsequent jobs without looking elsewhere.

The way I did it (I was taught this by a friend who does it more regularly) takes a bit of extra micromanagement for the first job, but it will pay off for subsequent jobs because you should be able to re-hire the same people. Post a job, wait until you have about 15 offers and then pick the top 5 (filter them on their English and whether or not they specifically respond to your post). To those 5, assign different pieces of your total job as a test job (less than 3 hours of work each, and limited by the hours/week setting). The most important part of Odesk hiring is communication - use middle school English and make it clear that they are to ask questions immediately if anything is unclear. Be friendly and be sure they know that you are happy to help.

Of the five people you hire for a test job, at least one of them will probably not even start it. Another couple might start but not finish. You will almost certainly have a few that do decent work, though, and even if they represent different skill levels you can leverage them across different projects. (I have a contractor from India who inserts content really nicely, but she can't edit themes very well. I hire her regularly for page content, but I pay her less than my contractor in Kenya who takes care of editing themes for me.)