How to Hire a Freelance Writer

I recently hired a cadre of freelance writers to cover a large project from a publisher. I've been quite happy with their performance and work, and thought I'd share some tips on hiring a freelance writer.

• Start with people you know. I went to a professional group I belong to, knowing that they shared some common beliefs, goals and knowledge.
• Allow them to convince you. I asked for a short letter outlining past experience and projects. I used this letter to judge how well these writers could synthesize information in short form.
• Follow up. If you don't already know your applicants through social or professional circles, carefully follow up on some of the projects and contracts they mention. Pick up that magazine article, or contact the client they offer for a reference.
• Be clear. After you've chosen your writers, the most important way to see yourself to the other side of the project is by being clear and direct.

How about you other freelancers out there? How have you managed outsourcing? Do you have any tips for the Google users who stumble here looking to hire freelance writers?