Weight is the term I use to talk about how important something should be in a story. In a lot of stories authors feel that the only way to make their characters real is to create some tragedy that they have to survive. The problem with this approach is that some things are heavier than others.
Killing a parent or a sibling is not something that a character will get over in a few days, weeks or even months. The same is true of other physical and emotional traumas. If you put some tragic in your story for effect, but then don’t deal with its lasting consequences your story will be out of balance. Instead of making your character look tragic it will make them appear uncaring. That can be a useful tool if you want to portray someone as a sociopath, but for the average character you need to think ahead about how the pain/grief/anger is going to change the way they interact with the world.
Conversely, a relatively minor occurrence shouldn’t be the case of a drastic change in the character. The exception would be the use of imbalance for comic purposes. The example would be a cheerleader who wanders blithely through life until she breaks a nail and goes thermo-nuclear. Exaggeration is one of the mainstays of comedy.
The other way that weight comes into play in a story is more important in longer works. This is how much time the author spends on something early in the story should be balanced by that thing’s importance in the conclusion of the story. If you spend six pages describing a log floating in the ocean, that log better have some importance toward the end. If it doesn’t the reader will be unconsciously watching for it and will get increasingly impatient. It is better if you don’t make it obvious that you are giving a lot of weight to something early on, but it can be a simple as giving it an extra adjective, or mentioning it more than one or two times.
It is amazing what the unconscious mind will store away for later. An example would be the bow in Hunger Games. A lot of words in different places go into showing what a great shot Katniss is with the bow, yet early on in the Games, she doesn’t have the bow. Then when she does, she hardly uses it. That way when it does come into play the reader thinks, “Ah, now that’s more like it!” and you have a satisfied reader willing to stretch their imagination just a little further.
The corollary of spending too much time on something of no importance is not giving a vital bit of information enough time. If you are going to have your heroine slay the werewolf with a silver knitting needle in the final battle of your book, you had better have made more than a passing reference to that needle in the second chapter. Again you don’t have to make it obvious, but mentioning it a few times or giving it some extra description will set it apart enough that the reader will think “Of course, she had it the whole time!” and be satisfied.
It is possible to use weight to misdirect the reader. I’ve read a few stories in which great time and care was spent describing a sword that was to be the hero’s salvation in the final battle. Only to have the thing shatter so the hero needs to scramble to get the real magic sword. The interesting thing was there were also a couple of clues scattered here and there to hint that the hero had the wrong sword.
Mastering the concept of weight in writing will make it easier to guide your story and your reader to a satisfying conclusion.