50 Tips for Writing.

29. Maintain a consistent tone

Maintain a consistent tone throughout the story. Whoever the narrator is and whichever perspective it is from, it's not very professional if the narrator sounds like a croaky old grandmother in one chapter and a giddy little kid in another. The style of the entire story should be dependable, remember what I said about choosing a main theme? If your story is horror, you can't just make it into a cute little romance all of a sudden, your tenses used in particular situations and the mood for each settling should flow smoothly from one scene to another. An evil carnival trapping two young girls and scaring the crap out of them wouldn't fit with a sudden change of the two young girls finding an empty cotton candy stall and eating all the sticky mush. They're supposed to be busy running for their lives! Being distracted is common when writing a story so either you sit on a finished chapter and come back a few hours/days later and re-read and edit or you can shove it at your Beta reader's nose and demand coffee.