Deciding on a Voice

One of the things that hit me when I first went back to school was the true lack of knowledge I had on point-of-view when writing a story. I remember well our first professor, Mike Lennon, the very talented author who is now working on Norman Mailer's autobiography. We were standing in the cafeteria, me nervously mingling with the other new students, he engaging in conversation with another professor.
All of a sudden he turned to me and said, "Do you know what point-of-view in story is?" His white bushy eyebrows were furrowed into a question mark. I,in my usual deer-in-the-headlights fashion, stood open-mouthed, my gaping hole filled with a half-eaten piece of pizza, and blurted, "Huh?" He whirled back the other professor and said, "See? They (meaning me) don't even know the basics." The disgust in his voice washed over me and I shuffled away, head down, a long piece of mozzarella still clinging to the side of my mouth.
Fast forward to now. I am just completing my educational piece (well, maybe completing) for this semester. I've had to dissect point-of-view (POV)and structure to the point of ad-nauseum. But you know what? Professor Lennon was right. I didn't know squat. I'd start writing a story with one point-of-view and then change the point-of-view without even realizing it.

Here's an example.

Emily's watched her mother move to the kitchen window. Maureen hated days like this, days when gray covered the sky like an unopened umbrella.

The story starts out with Emily's POV, but snaps into Maureen's POV. How do you know that? As the POV character, Emily cannot know that Maureen hated the day unless her mother had used dialoge telling her such. Everything thought must come from Emily's point-of-view for the reader to understand story. When the author changes point-of-view, they must use distinct triggers so that the reader will understand the point-of-view has changed. The better use of the second sentence to keep it in Emily's point-of-view should have been:

Emily's watched her mother move to the kitchen window. She knew her mother hated days like this, days when gray covered the sky like an unopened umbrella.

See,even being blonde and married to a pollack, I AM learning something!