on Just Publishing Advice:
When you sit down to edit a book, you want to improve your story and your writing.
It’s a good idea to do a thorough grammar and spell check before you start. You have a choice of plenty of premium and free grammar checkers to help you.
But a grammar check is not editing. The editing process starts when you carefully read your manuscript, line by line.
If you don’t have a professional editor, you can learn how to self-edit your book by following my checklist of 20 common faults.