Point of View
Point of View is easy to define, but difficult to maintain. Whoever is viewing the scene for the reader is the POV.
Imagine, if you will, that the book is recorded by a reporter with a camera. The camera can only record where the reporter is located. The location of the camera, relative to the reporter - your character - determines what type of POV to use.
The camera is inside the character's head. It sees through the character's eyes. Because it is snuggled inside the brain, it can hear every though the character has. The reader is up-close to the story but is limited to seeing and hearing only what the reporter notices, and the reader is stuck inside the head of that one character. (Unless the writer has two characters with camera implants, and that rarely works.)
I heard a strange dripping sound just around the corner. In spite of all my years of watching horror movies, of yelling at those idiots to run away from the obvious danger, I forced my leaden feet to take me around the corner. My eyes had just enough time to focus on the droplets in front of me before ....
The reporter is standing opposite the reader with the camera stuck in the readers' face. Being the most stereotypically obnoxious reporter possible, every action the reader takes is said out loud. (This is rarely used as it is clumsy and often annoys the reader.)
You knew there was a reason no one ever went to the ruins of Happyland Park, but you had to be the first, had to be the one to tag the place and make it your own. Oh, a small set of initials just inside the walls wasn't good enough. You bought three cans of day-glo green so even the yuppies over on The Hill would know your name.
Limited Third Person
The camera is strapped to the reporters head. Wherever the reporter looks, the camera shows. However, the camera may catch things that the reporter does not. The camera will catch anything the reporter says as well as whatever she mutters under her breath when she thinks no one can hear her. The straps on the camera can be removed and the camera can be placed on a different reporter when the need arises.
What a hick town this was! Only one movie theatre, no mall, and nothing better to score than some low grade pot. He kicked an empty beer bottle down the street. He was half-tempted to take a baseball bat to one of the ever-present pickup trucks, but who'd notice a few more dents? He saw a flutter of movement from the corner of one eye. It was an old flier for some lame-ass amusement park that was gonna put this place on the map. Well, hell, he might as well go prowl the old wreck, see if there was anything left to hock.
Omniscient Third Person
The camera is still tethered to the reporter, but it's also attached to a balloon, so it floats high above the scene, capable of looking in a different direction than the reporter. While the reader gets the best view of the entire scene, the reader is also the most removed from the story. Be careful when using Third Person Omniscient. It is very tempting to point the camera all over the place, but be careful - the reader may get dizzy with the constantly shifting view.
Moving was never easy, but fleeing an abusive father in the middle of the night was far worse. As Susan silently slid the last box into the back of the van, Darren slunk around the corner. With a sneer permanently engraved into his sixteen-year-old face, everyone knew it was only a matter of time before he took after his father. More than a few hoped he'd go after his father with a baseball bat, but no one counted on it. Darren jerked his head to the front of the van. As soon as she got in, he'd push the van down the driveway so the engine wouldn't wake the old drunk up.
Always remember where your camera and reporter are, and you'll be able to keep your POV consistant.