V is for viewpoint.
When it comes to writing fiction, viewpoint looks fairly simple at first: Will the story be in first person or third? Single viewpoint or multiple? Even when a story has only one viewpoint character, however, choosing whose viewpoint may require some thought.
In the tales of Sherlock Holmes by Sir Arthur Conan Doyle, the stories are about Holmes, but Watson is the viewpoint character, because Holmes knows too much. Had he been the character through whose eyes we saw events, the author would have had to choose between deliberately withholding information that the character knew about, or destroying the suspense by revealing the solution to the mysteries far too soon. Because the reader sees events unfold through Watson’s eyes, the problem of too much information or not enough is avoided completely.
This is the kind I had with one of my own novels for a while. I had three different characters who had major roles in the story, and I was having difficulty deciding which one made the best viewpoint character. Two of them, though, knew too much about either the story’s current events or past events that affected the current situation. The best choice was the third character.
That character was the best choice for viewpoint for another reason, too: she had both motivation to get involved and the freedom to act. A mistake that some new — and not-so-new — writers make is creating viewpoint characters who would not reasonably be able to take direct action in the events of a story, or who lack believable motivation to do so. It’s no fun to watch a story through the eyes of a character who doesn’t get involved in anything, who only watches from the sidelines. (And why would anyone create a character like that in the first place?) It stretches the bounds of believability that a monarch would be able to just drop everything like, y’know, ruling their country and go off to pursue personal adventure; that character has power, but realistically doesn’t have as much freedom to act as the son or daughter of a mere baron.