The best resume writers understand recruitment 
Before you hire a resume writer, make sure that he or she has a background in recruitment or HR. Unless a resume writer understands how companies hire, little else matters. I often get asked if I have experience writing resumes for professionals in one field or another, but that’s the wrong question to ask. Yes, I’ve worked with job candidates in almost every position for almost every industry, but more importantly, I’ve HIRED them as well.
I was a human resources professional for many years during which I hired hundreds of people for every position imaginable, from the call center to the c-suite. That means that I was the person who decided whether to hit “delete,” or put a resume aside for further scrutiny. And that means that I know how HR and hiring managers think.
A good resume writer understands that resumes are marketing tools
In addition to being a good writer and having a background in recruitment, your resume writer should grasp that your resume is how candidates market their skills and experience. That means guiding clients into dropping irrelevant details that add nothing to a candidate’s value proposition.
Does Professional Certification Matter?
Personally, I think these certifications are worthless; so is belonging to a professional resume writers’ association. I’ve seen what some of those associations consider a good resume, and I refuse to get accredited by them.
How to choose a professional resume writer