The process of manuscript editing is a fairly simple one. It just takes time and patience. There are a few simple techniques and a few things to keep in mind.
Spell Checking and Grammar
I always run spell check and grammar check when editing, and I write in a Word document. Things spelled wrong are underlined in red, and bad grammar in green. That is only turned off when the book is ready to publish. Certain sentences in the final product may still be in 'bad grammar.' But if that happens, it happens for a reason. A conscious decision was made, due to artistic considerations, perhaps using contractions, or slang in dialogue for example. When I come across a word that the computer doesn't seem to know how to spell properly, and I'm almost but not quite sure I'm right, I Google it and look for it to pop up. In editing my recently-completed book, 'On the Nature of the Gods,' I found that in Canada, it's correct to spell 'sulphur' as you see it here. In the U.S., you could spell it sulfur or even sulfer and get away with it. Which one I choose depends on a decision-making process, not simple ignorance or carelessness.
I wrote that book to the end, that is to say I finished the plot. It came out at 60,500 words more or less. That book, after three major edits/rewrites, made it up to about 67,000 words. It grew because of added details, clarification, and all of this in spite of the fact that I probably eliminated 300-400 words that really didn't need to be there.
The trouble with making up names, using foreign words and colloquiallisms, is that the computer sometimes says it's spelled wrong when in fact it is right. Each and every one of those, has to be visually checked, one by one, and this is a separate scanning process where I don't actually read line-by-line. It involves scrolling down, endlessly down, and stopping at each and every thing still underlined in red.
The editing also includes the front and end matter. I want the proper disclaimer, the proper ISBN, and stuff like that to be right, 'on the first upload,' for someone could buy a book within minutes of publication. I don't have a whole lot of trouble with its versus it's, or there/they're/their, but if you do, the computer might not catch those, so have an eye. Sometimes the computer doesn't know a word is missing from a sentence. It's a lot of reading, over and over again, to pick off as many errors as possible.
Formatting and design.
When formatting, I turn on the pilcrows, and make sure the spaces are the same. I use single spaces, 12-point, although chapter titles are in 14-point. I don't want a 14-point space to creep in and throw off the depth of my chapter headings, right? This involves a couple or more run-throughs, again not necessarily reading the book, but if I saw something wrong I might fix it on the way by. The pilcrows are only turned off and on when checking formatting, to edit with them on is a pain.
In terms of design, the e-book can be dead simple. One thing, always include a link to your website. My books have one at the front and at the back after a short bio. Other than that, the right edge is ragged, not justified, and the chapter titles are centred...etc.
Proofreading is important, and if you can get someone else to read it, that would be wonderful. Make sure they are good spellers, and hopefully they are the kind of person who is not a procrastinator. Explain that this is not a review or book-report.
Tell them, 'Just look for typos,' and, 'mention anything you didn't really understand clearly.' Never rely on another person to do your work for you. I don't care who they are, you would still have to read the thing yourself before publishing it.
No one else can take responsibility, nor should they. This is your baby. Never forget that.
The first time I published, I must have rewrote twelve or fifteen times for my first two books. At this point, a year and a half later, my copy is a lot cleaner first time out, and so much less has to be cut from the story. It doesn't take so long anymore. There is a temptation to publish the thing as quickly as possible and to start making some money. Every independent author feels this way. There are no shortcuts to a job well done, and that's exactly what my old man used to say--so you know it's real.
'On the Nature of the Gods' took about two and a half months to write, maybe three weeks to edit, and it will be published on or about March 31.