Don’t fall down on the easy stuff. If you’re writing a novel and sending your manuscript to a publisher, it has to be in perfect shape. Make sure that you can tick every box before you consider your novel completely finished.
Technical
Have you run a spell check on your entire manuscript? (If you have problems with the passive voice, run a grammar check too.)
Have you made sure that character names and place names are consistent throughout?
Is the chronology correct?
Language
Is the language in your novel clear and understandable?
Did you make sure that the text isn’t overly complex, verbose, patronising or obscure?
If more than one comma is in a sentence, should it be two sentences?
If you use more than one adverb and adjective in any sentence, are you sure you need them? In fact, is every one of them necessary?
Character
Are all your novel's characters utterly necessary? Would the story be tidier or faster if a minor character was removed or merged with another?
Are all the characters easily distinguished from each other? If you have two characters, both aged 30 with red hair, both married to tall men called John, one called Marion and the other Miriam, merge them into one.
Do you have a strong main character?
Does the reader have a reason to identify with the main character? (Remember, ‘identify with’ isn’t the same as ‘like’. We only need to be interested in the characters and want to know what happens to them, we don’t necessarily have to fall in love with them.)
Does your protagonist have a strong antagonist; someone who wants the opposite of what they want?
Style
Have you checked that, wherever possible, you’re ‘showing’ and not ‘telling’?
Is your text colourful in the sense that it isn’t unrealistically simplistic? Things in real life are rarely pure and seldom simple. If you present them as such, your book won’t seem realistic.
Theme
Does your book have a theme?
Does it say something about something, whether implicit or explicit?
Do you know what sort of book you’ve written?
What genre (or genres) does it fall into?
Does your book have the characteristics of that genre, and if not, what have you put in their place to keep the reader interested?
Dialogue
Is the dialogue within your novel realistic?
Do you use ‘he said’ and ‘she said’ instead of ‘he expostulated’ and ‘she exclaimed’ and as sparingly as possible, only to make it clear who’s talking?
Do all the characters sound individual, or do they all sound the same?
If the characters are all the same age and social background, have you put in phrases and individual modes of speaking to help the reader tell them apart?