Like Jef, I too have used UpWork/Elance for some time. Much less so these days, not because of any bad experiences, simply because I find it too hard to distinguish between a huge number of competing freelancers.

The platform I'm currently using for outsourced dev work is PeoplePerHour. I like the recommendations they provide and find their system much easier to work with.

Another I also recommend is Envato Studio. A lot of good WP designers and developers are available, each of whom is vetted before registering.

And it's this lack of third party quality control that's at the heart of the UpWork problem.

I've used the platform on and off for a while. I've tried to land some side gigs on there with no avail, but I do know that there are some developers and other professionals making decent money on that platform.

I've had good results using Fiverr, but you really have to complete a lot of due diligence so you aren't disappointed with the results.

Look for people with high ratings and positive reviews. From there connect with them in a conversation (direct message, email) to ensure they understand what you are looking for and are comfortable with your expectations and timeline.