While writing we all make mistakes. It happens. Why? Because we're human and we are not perfect creatures.

This is why we edit and edit some more.

Issues arise when we go back and something has been worded so badly even you can't figure out what you were attempting to say. Try not to get ahead of yourself, especially if you just frantically typed out something because you were super excited about the scene. Frantically type it, but go back and reread it before moving on to be certain what you wrote out is what you were going for. 

I rarely co-write with anyone because I'm extremely OCD about how I write and it annoys me when things aren't done a certain way, even if I understand we don't all have the same writing process. A while back I co-wrote with a good friend of mine and two of her friends. I was super excited to write the book because it was a S.H.I.E.L.D. fanfiction. During the entire thing, there were times her two friends drove me insane and I considered backing out of the project. Their writing habits and lack of research drove me nuts. They both vanished from Wattpad and we never did finish the book.

The three of them started another book that I wasn't involved with as far as writing but I was assisting with the editing. That would be where the whole "don't get ahead of yourself" thing comes into play. 

One of the girls wrote this sentence (I'm still not certain what she was saying) -

But that would have to wait until after today, she thought to herself. She had many things to do, just as she did the day before that, and the night previous to the next.

Here's another one -

Her feet were bare but her pant legs waded in the water below her knees.

I laughed loudly when I read that line, I pictured a pair of pants wading into the water all on their own. There were many more very badly written lines. At one point she said the girl ran into the campfire, not walked into the light of the campfire, just into the campfire. I pictured the girl running, her arms in the air as she screamed and ran right through the fire.

You need to pay attention to how you're wording things as you write. Not only how you phrase things but also that you're using words correctly. 

If your characters are walking, you want them on the beach, not the beech. The first is a nice sandy stretch of land by the ocean, the second is a tree.

You want people to be mourning the deceased at a funeral, not morning them. 

Lightning flashes across the sky, not lightening.

These are only a few examples of words that I've seen regularly mixed up.

Language differs from country to country as well. American English is very different from British English (for example). If you're using one or the other be consistent in your usage. If you're publishing in the U.S. then you'll want to write in American English. Not to say if your book is set in England the characters need to speak it, but as far as formatting and the general read of the book, style it more toward American readers. We'll harken back to Harry Potter as an example, the characters use British terms for a lot of things. What is a flashlight in America is called a torch over there. Phrasing differs but you need to make certain the book is understandable to the audience you're targeting. John Flanagan is an Australian author who writes the Ranger's Apprentice series the books published in Australia have a vastly different look than the ones published in America. Over there he publishes in British English, here in American English. The formatting of the books also differs. Over there they don't use quotations around speech, they use a single quotation. 

"I'm sure that's correct."

'I'm sure that's correct.'

You'll need to learn what editors and publishers are expecting where you plan to publish if you want your book to be accepted for publication.