What role do you picture your editor taking in your writing process? Your editor's goal is to help you craft the best book possible, but that can only happen if there's clear communication between the two of you and a clear agreement of process and goals. Many professional editors get frustrated with author expectations, especially those held by first-time authors. If you could ask your editor about her biggest author frustrations, it's likely she'd mention at least a few of these situations.
It's important that you have a talk with your editor before he begins work on your manuscript. If you don't want to follow certain grammar rules, that's fine, but he needs to know that. The same goes for any style choices you may have made, deadlines you need to hit, and expectations of the frequency of communication. Working this all out ahead of time will save both of you a world of frustration.
Don't Be Stubborn
The reason you hired your editor is to improve your work. Trust her, she's a professional. Improving your spelling and grammar are not "changing your voice," they're simply ways to make your text easier for readers to enjoy. In other words, consider everything in your first draft fair game, and be willing to change anything in there to improve your book.
Have Some Pride in Your Work
Your editor isn't the housekeeper hired to clean up every bit of your mess. She's there to polish things after you've put forward your best effort. Go through your manuscript multiple times to look for typos and grammar errors. There are about half a dozen reputable editing apps online, and many of them are free. Invest the time to use a few of them to get the cleanest copy you can make. Only then is it ready to send on to your editor.
Don't Be Impatient
Writing your first draft may have seemed like a long process, but you're far from finished. Writing a book takes a long time, and the editing process can take just as long as the writing does. Quality books require multiple editing passes before they're ready for publication. Don't try to hurry your editor along just because you're eager to see your book in print.
It might feel like it, but it's really not personal. When your editor starts suggesting that you cut out your absolutely favorite parts of your book, she's not doing it to be cruel. She really does want your book to be better. If you don't agree with something she advised, have a calm discussion with her. Don't get mad, don't lose your temper, and don't refuse to consider the advice she gives.
It's your book, not your editor's. He'll send your book back, pointing out issues like point of view or sentence structure. This doesn't mean you need to do a once-over pass to be done with the book. When he points out an issue, it's up to you to go through your entire book and look for similar issues wherever they crop up. If it happens once, it's likely to happen again. Revise your book, start at the beginning and revise it again, and keep going until all the parts fit together seamlessly.
Don't Be a Quitter!
Yes, bringing a book to publication is a long and complicated process, but getting frustrated and quitting doesn't do anyone any good. Everyone's tempted to quit once in a while. When frustration overwhelms you, set the book aside for a day or two and work on your next first draft. Give it a couple of days or even a week, then get back into it. Looking at your book with fresh eyes might be just what you need to push you through to the end.
Keep the Faith and May the Force be with You!