To distinguish the good resume writing services from the bad ones you need to find out how they proceed with the task. A good service asks you to fill out an online question. They also set you up for an interview with the writer. This ensures that the writer is aware of all details that must be present in your resume. If a personal interview is not possible they may also provide you with other ways to get in touch with the writer.
Ask yourself - is a cheap resume of any worth if all it does is extending the period of your job search? The answer is simple - no. The cost should not be the sole focus when you choose a resume writing service. The priority should be on the quality of the final product. Only a unique resume that captures the attention of prospective employers and guarantees an interview call is worth your money.
Add in a list of skills Your resume is no place for modesty. Highlight your skills especially if they are specific to the job youre applying for and list where you gained experience with that skill set. Instead of being general give concrete details and highlights. For example list your experience with Microsoft Office or even a particular piece of software over computer skills. Make sure to include plenty of competency statements.