There are far too many point-of-view options to get into here, but suffice it to say, it can be tough to keep a consistent point of view if you have a lot of characters.
Writing in first person ("I" and "me") is fairly easy for me, which is why I wrote In the Days
in that POV. Most of the story took place in one character's head, and the reader saw the world through his eyes. It's pretty easy to keep things straight if you write from this perspective.
Now, get out of the single character's head and go to a narrator's point of view, and now things get a bit tricky. You have to make the tough decision of how much of each character's thoughts and feelings to write about, and how much you need to show through their expressions, their words, etc. Choosing the right POV is an entire manual in itself, but here are some tips to help you keep consistent with your narration and description.
Stay consistent with the POV
Are you in Bob's head as he stares at Margery? Don't tell us what Marge is thinking or how she feels. Stick in Bob's head until the scene changes or you make it very clear that the POV is changing.
Don't expect the reader to know who is who
When you're writing, you're telling a story trapped in your head. You know the characters inside and out, and you know who is thinking what and when. Your reader, on the other hand, is not going to know your character from Adam, so make it very clear what thoughts are in whose head. You may hate the "he thought" tag, but it certainly makes it clear who is thinking what.
Be careful with the "he knew"
If Harvell really does know his wife Wilhelmina so well, he would definitely see the signs of her anger--the furrowing of her brow, the clenching of her cow-like jaw, and the baring of her fangs. Instead of saying "Harvell knew his wife was getting angry", try writing it "Harvell saw his wife's moustache furrowing along with her unibrow. Uh oh,
he thought, I'm in trouble."
It makes a small difference to the writing, but makes a HUGE difference to the reader.
Separate POV scenes
Are you in the head of your amazingly seductive assassin one scene, but make the leap into the head of the poor john she's about to kill next? It may be a bit unwieldy, but try to switch POV only when you switch scenes.
These are just a few helpful tips from someone currently struggling with POV issues of his own. Trying to write The Last Bucelarii
in third person is pretty tough, as I do so much better in first person. Still, it's an exercise in improving my writing and avoiding another one of those silly Writing Mistakes!