One of the best things you can to do make the most of your editor's time is to ensure that you proofread your manuscript as thoroughly as you can beforehand. Does this seem like a bizarre statement to you? After all, the job of the editor is to edit and/or proofread, isn't it?
But consider the issue more carefully. Many editors work on an hourly rate even if they charge per project. A good editor knows approximately how long it will take her to work on a manuscript of a certain length, and she factors this into her rates.
Is the manuscript you send to your editor filled with extra spaces where you hit the spacebar too hard, rogue punctuation that has been left over from odd sentences you deleted, inconsistent use of quotation marks, characters' names in lower case because you forgot to press "Shift", simple spelling and grammar errors, and typos that are due to your fingers accidentally hitting two keys at once? If so, you're wasting your money while your editor wades through all these unnecessary corrections before she can spend the rest of the allotted time on your actual story.
I've known some writers who feel they need to test their editor by deliberately including errors in their text. No editor is infallible, but many editors pride themselves on a very high catch rate. By all means, feel free to play games with your editor, but remember that it is your money that you are wasting. Or, if your publisher is footing the editorial bill, bear in mind that you could be setting yourself up to be labelled a high maintenance writer, in which case your book had better be worth the hassle.
The type of edit may also depend on the stage of the project you are working on - an editor checking the characterisation and plotting of a first draft may decide to note a particular typo or spelling error only once in order to focus on more important aspects of the edit. He may simply state that the text has, for example, "excessive use of participle clauses" and leave you to do your own search and rewrite. Different editors have different styles, and you may, or may not, be the type of writer who needs an editor to point out each participle clause. If you can choose your editor, bear this in mind when you're drawing up your criteria.
Clean copy is a pleasure for an editor to work with, and the writer who produces clean copy can easily win the editor's respect. A manuscript with limited errors is also less distracting to read, and the editor can focus more deeply on the narrative and construction elements.
Remember that your editor is there to help you create a better book. Meet him as far across the half-way mark as you can, for the sake of your story, and your wallet.
What if you could clean up your grammar errors the easy way? Grammarly is an automated proofreader that corrects errors in your text, generates citations, and includes a Free Check For Plagiarism (Affiliate link)