The best resumes not only present cold, hard facts – they allow a bit of the personality of the applicant to shine through. When you write a client resume, you will be working with a limited amount of time with and information from the individual.
If you work remotely, you may obtain clients from different countries. You'll always need to research resume styles in that country and ask the person exactly what they want and where they are applying.
One of the benefits of freelance resume writing is the cost of operation. Likely, you will have little or no overhead, as you probably already have a computer, office furniture, and an internet connection.