Having a copyeditor evaluate your manuscript is expensive, so you need to follow some simple steps to get the most for your money. First, be clear as to how you'd like your manuscript edited, so that the editor will not make major adjustments which will cost you time when completing your manuscript. Following are a few tips to allow you to work with your copyeditor.
Copyeditors have a great deal of hands-on experience with editing and modifying documents; this can benefit you by improving your final product. However, the experience and preferences of the editors can also negatively impact your manuscript is the wrong style guide is used, or the manuscript is edited using the incorrect tense or person (e.g., first v. third)!!!
The initial recommendation, then, would be to provide your editor with clear guidelines. Specify the style you would like to use, whether it be American or British English, and the style guide your institution requires. For example, if this is a thesis, offer the editor the institutional and advisor