It is often the fools who learn from their mistakes, while the wisemen would rather believe they had made none.

Writing mistakes often made by young authors...

1. A foolproof plot-line, until the wings are grown and things begin blowing up.

One thing that young authors tend to do while they are coming up with their plots is try to show the world just how creative they can be. (No one doubts that you can be creative). These authors need a better means to express their creativity rather than in flimsy portrayals and excessive character building (character building can be a good thing, but too much can make it seem like you're stressing your character to be who you want it to be). Just bear in mind that while you a writing your novel, you cannot have believable characters that fly and cause explosions with but a thought; these characters cannot teleport and be vampires who can sparkle in sunlight - because these things happen to be ridiculous. (The exeption to this being James Patterson who wrote the Maximum Ride series). 

Now, to help you rather than chastise you I will explain how to write a good plot-line.

• First and foremost, what you must do (under no circumstances is this step able to be skipped) is brainstorm - this is something that needs to be done if you even going to bother writing something. If you don't brainstorm, you'll have a lack of ideas, and a lack of ideas makes for a rather short novel.

• An informal second step would be to search for your inspiration. Look around the bookstore, open a couple books and read their beginnings, then take some others and read the middle. Never forget to check out some dialogue - if you want to create great character conversations then check out some who've done it already. You wouldn't want a conversation that ends up sounding like a bunch of onomatopeias. 

• Third step? Ah yes, the basic characters that you need to create in order to have your players. Think of it as a football game - your main character is the prize quarter back, and the others are secondary, third and fourth characters that help the quarter back get the ball to the end of the field. This is what you need. (While some authors like to do long and structured character builds, you won't need that until later on).

• The last thing that I will give you, that you need, would be the understanding of the cause and effect which the understanding of chain reactions. A chain reaction is when a cause - the main character has just stolen a prized jewel from its hidden underground placement - elicits a reaction - the underground tunnels begin to collapse -. 

I'm sure you can go on from here, yes? Just remember that a horrible plot-line and a missing plot-line are much the same things: they both do not keep a reader's attention.