The goal of the read-through is to see your work as a first-time reader would. That's important because most writers wear blinders. We mentally skip over stuff in our own writing. We just don't catch it all. Reading as a reader would, allows you to see your manuscript from completely different eyes. But it requires several steps. All are vital to making this work.
1. Move your manuscript out of Word or Scrivener. Within a text-editor, it's nearly impossible to read as a reader. Print it out or send it to your e-reader. I use Pages on my ipad.
2. Set aside time to do this. It's onerous. I find it usually takes me two weeks.
3. Read aloud if you can. You'll catch a LOT more this way.
4. Don't edit as you go. I can't emphasize this enough. Just mark the spots that catch your attention and may need fixing. In Pages, I highlight the word and click on comment, but leave the comment blank. It creates a yellow highlight on the page, which I come back to when I'm ready to fix. If you've printed out the manuscript, even easier--use a colored highlighter and make a slash mark in the margin.
Many writers cringe at this guideline. They feel they'll forget what idea or fix they had, when they come back later. In my experience, this rarely happens. I always seem to remember why the sentence or word didn't work.
If you start editing, you slip back into writer mode. You have to start over as a reader. Trust me on this one. I have read many manuscripts from clients or when I worked as an editor that lost their juice midway. I suspect the writer did well in the read-through until this point, then got seduced into editing and never regained the reader viewpoint.
5. It's best to read the entire manuscript before going back to edit individual chapters. You'll catch chapter-to-chapter transitions this way. If you only look at individual chapters, you'll miss this and your book may feel like separate anecdotes rather than a sequence of chapters.
Once you've completed your read-through, take a break. Several days, a week, even. It's been hard work, so relax that brain.
Then, when you're ready, come back to the printout or the e-manuscript and look at what you highlighted. Let the ideas and fixes begin to pop into your mind. Bring up each chapter on your computer and start repairing, expanding, deleting.
I recommend a final read-through, after you make these corrections. Sometimes, I do several more. After all, I only get one chance with most editors and agents. I want to make the book the best it can be.
Your Weekly Writing Exercise
If you're not ready for a full manuscript read-through, try a couple of scenes or chapters. Print or send to an e-reader and practice reading as a first-time reader would. Highlight, don't correct yet, and see what you find.