1. Only hire individuals. Never hire a team.
2. Watch out for individuals who are secretly fronting a team.
3. Make sure that you have a keyword in your project description that has to be mentioned in the bid by the freelancer. This will allow you to weed out 95% of freelancers who bid without reading.
4. Chat to the freelancer about the project first and if possible hire them for a small private project to scope out the details.
5. Despite all these steps expect only 50% of freelancers to workout. Either hire two at once or schedule enough time to do it sequencially.