Excerpt from Success, Your Path to a Successful Book by Maralyn D. Hill and Brenda C. Hill.
You may have a friend or a family member that is an English teacher who offers to read your manuscript. That is ok, but don’t have that person be your final editor. Money spent on a professional editor is money well spent. Be sure you have someone edit your book who is used to editing for style, dates, grammar, spelling, and consistency.
When you are editing, it is a good time to look for words or phrases that can be replaced by more effective ones.