#editing errors

Time

This includes character ages (especially in flashbacks and exposition), the beginning and endings of school years, the seasons and their weather patterns, moon phases (especially when writing about werewolves), times of day, how long it takes for events to happen (a wound to heal, DNA to come back from the lab, traveling from point A to point B), historical matters (phraseology, having characters use things that hadn't been invented yet, people in the middle ages eating potatoes, etc.) and so on.

One time, I was reading a WIP where their main character's (or MC's) sister, who was twelve, was being discussed. The MC said that her sister had been dating someone at the same time the MC was first learning to use her magic powers. Fine, except that later it was stated that she first learned to use those powers five years ago. Which would make the sister seven at the time. Ain't no seven-year-old datin' nobody. The author of the WIP had just forgotten that all the characters ages would change, not just the main character's.

In my own writing, I had to be very careful in Outcast Shadows, because two groups of characters were in two locations doing two things: Group A was traveling across a continent, while Group B were hanging out in a single building in a single city. But they had to meet up at the end of the book, under specific circumstances, so I had to make sure that both storylines took the same amount of time. In the first draft, Group A took far longer than Group B, which was disastrous! I had to go back and, first, measure exactly how long it would take Group A to do all their traveling and find things for Group B to do that made sense for the story to fill up that specific amount of time.

As careful as I was in Outcast Shadows, though, I completely forgot that Misha left a certain location a day earlier than everyone else in Recast Light—and this was after four rewrites. I had to account for what he was doing for an entire day, which meant rewriting several scenes. It ended up working out in the end, but is a cautionary tale I won't soon forget.

Place

This includes anything spacial, such as the layouts of rooms, buildings, cities, and continents; the blocking of character movements; light sources; the configuration of the the solar system; and so on.

For example, if your character was flat on his back a few sentences ago, but now he's standing, were we ever told that he got up? Did your characters, while touring the lower rooms of a castle, ever climb something in order to get to that second story room where they end up (mine didn't, in the first draft of Miscast Spells!). If your scene takes place in a dark and dingy torch-lit tavern, how can your characters notice tiny details, or are you picturing the scene as brightly lit as it would be with electric lighting?

Obviously, some of this can be fudged a bit—I don't think anyone but me cares about how scenes are lit—but some of it can't. And readers will notice. There was the famous case of Larry Niven's Ringworld, in which a character is teleporting east in order to extend his birthday, but of course the earth rotates east, meaning he would actually be moving later into the day, or even into the next, rather than earlier. So many readers noticed that Niven actually corrected it in later editions. Then there is Stephanie Meyer's Breaking Dawn, in which the Cullens have a house on an island off the west coast of Rio de Janeiro which, you know, doesn't have a west coast. These authors had professional editors who didn't catch these mistakes, so you can't rely on other people to notice continuity errors for you. Do your own research and know the layout of your own setting, especially if it's the setting we all live in.

People

This category includes what your characters have, what they know, and who they are.

For what they have, consider clothing and accessories, weapons, and useful items. If they don't have an umbrella, but it's raining in your scene, do they just stand there in the rain? Do they like it? Aren't they cold? If your character has some huge rucksack full of gear, they should always have that rucksack full of gear unless we can assume they left it in a safe place; if they're traveling from one end of the continent to the other, mention how heavy that rucksack is from time to time, and consider where it is during a fight or action scene (Are they still carrying it? Do they drop it? Do they pick it back up when they flee?).

Another thing that characters can have is injuries, which, unless magically healed, have lasting effects. If your character got punched in the face yesterday, they should have a bruise show up in a day or two, and last for about a week (she writes, realizing that she has had a character bruise far too fast in her own published book!). If your character has lost a lot of blood, or broken a bone, or received a concussion, all of that needs to be taken into account in the coming chapters. Again, this can usually be solved by a quick mention that such and such still hurt, but injuries will also impact how much traveling and fighting your character can do, so keep that in mind, too.

Be mindful, also, of what people in your story know, including POV and non-POV characters. A pet peeve of mine is when authors in multi-viewpoint narratives slip up and have the viewpoint character be privy to what other characters are thinking when there is no reason for them to know that. Then there is the opposite problem, typically in first person present tense stories, where, in order to have exposition, the MC will randomly be thinking about information that everyone in the setting already knows. It would be like reading a novel set in our world and having the first person narrator think "243 years ago, America declared independence from Britain, which it had formerly been a colony of. This was followed by what is known as the Revolutionary War, where the Patriots, on the American side, fought the Red Coats, the British soldiers". No one thinks that way, because they personally already know it; who are they explaining it to, themselves? Find a more natural way for this information across to the audience. Maybe the character is arguing about it with an friend or is helping a younger sibling with their homework.  For this sort of thing, dialogue is definitely your friend, but still, double check to make sure this seems natural.

Finally, think about who your characters are, as opposed to who you wanted them to be. Characters change and grow over the course of writing, and what you might have considered in-character when you were outlining the novel might be out-of-character now. Consider your character's emotional reactions, moral choices, word choice, and so on. Never let an intended message be a reason to railroad a character into some preconceived destiny. Take the time to look at your character, not as a writer, but as a reader.