It is imperative to know about the basic qualification of the person you intend to hire. If he/she is a graduate in English literature don't be too happy about it because they might not be able to write creative contents. Read through their resume and find out if they have been involved in writing or editing their work related documents. Sometimes this skill will help to know that they would be accurate in pinpointing grammatical errors. Besides, they would have an eye for reading each sentence word by word. Anyway, it is best if the writer is a graduate and has worked for few years.