What makes up a plot, exactly?
1. A plot needs a beginning. All stories need beginnings, surveys show. So we have the "Once upon a time"--a very nice, traditional beginning.
2. It needs a character to be introduced. Enter "there was a little troll."
3. Now, the character is described. "She was a very good troll."
4. Now that we have our character, we need some conflict: "...she didn't like to eat her dinner."
5. After the conflict, comes the resolution. Oops, loving the little trolls does not resolve the fact that she doesn't want to eat her dinner. This story does not have plot.

In this column, I will be talking about the first part of a plot:
The Beginning

I suppose it's pretty obvious that a beginning comes in the, well, beginning of the story. It's the part that grabs the reader's attention. I like to think of the beginning as being water. The reader is thirsty. Your job is to give them a glass of water, to quench their thirst. If there isn't enought to pique their interest, the reader finds the beginning dry, and goes away to find another glass of wather. If there is too much mystery, the reader is at first drawn in, then drowns in the excessive intrigue. Drowned readers never get far either.

So how do you know just how far you've gone? Let's say that Susie is a writer, and she wants people to read her story about a frog in a pond. She writes,
Alistair is a frog. He lives in a lake. There was a fish in the water that was really scary. Of course, the water was murky, so the other frogs never saw the fish, but they were still scared.
I'm guessing if that went on much longer, even the most patient of you would stop reading. How about if she went to the opposite side of the spectrum?
Lightning flashed over the lake, and the creature shivered. He was an animal of the pond, but he dared not descend into it's murky depths. Rumors of a terror lurking within had kept his kind away from the waters.
I'll throw you a life preserver, and we can get on with the column.

The first example left you with no important questions. Maybe you might wonder what made the water murky, or idly suppose as to how the frogs survived without water, but there's no hint of conflict, nothing to interest you, the reader (unless you are absolutely devoted to stories about frogs.)
As for the second example, it leaves you with many questions. Who is the shivering creature? What kind of animal is he? How deep is the pond? What's the terror? The author has missed the boat and tipped the scales towards drowning her readers.

So what could Susie do?
Here's an example of a possible paragraph:
Alistair had always heard the tales the old frogs told of the pike that lived in the pond. As a child, his mother had always watched over him as they swam in the water, keeping to the shallows when possible. He was a good frog, and it had never even crossed his mind to go over the deep waters of the pond. No frogs ever swam there, or so he thought.
Admittedly, this is not an amazing feat of writing, but it does combine some elements of the two examples above.

Another thing to watch pertaining to mystery, is the lenghth of time the mystery goes on. When you mention something over and over again, and don't clarify it, it becomes nothing more than a redundant annoyance. Part of the mystery is to hide even the mystery from the reader. Be subtle.

Though beginnings seem to be the easiest part of the story, they actually require a lot more thought than most of the other parts. Devote a lot of time to your beginning, come back and rework it from time to time. But remember, always save your many beginnings, so that you never lose something you might want to use later. Keep a file on your computer of the "rejected" beginnings. They may come in handy.