An info dump is a term used to describe what a writer does when they give away too many facts and details in one lump. A reader can be easily bored with too much concentrated description. So now take a look at the picture again and imagine the trash as the "info dump" in your story. It looks just as ugly within your pages as it does in that picture.
Here's some general rules to follow to avoid exposing your potential agents and editors to info dump:
- Is it necessary to the story? A small amount of description is usually needed to set the scene but nothing more. For example, if you are describing the small town your character lives in but mention that there is a mall in the city an hour away for shopping, you need to omit that, even if it will be part of the story later on. No one cares to know that there is a shopping mall in another town. And it is doubtful that information will be remembered by the time it is required for the story.
- Have you already described a room or place? It's very tempting, later in a story, to create the scene again by re-describing the setting. It isn't necessary. Only include items that may have changed since the reader was there last.
- In fantasy and sci-fi, it is NOT advisable to write down where every planet or continent is, who lives there, how many stars a planet has, where the magical creatures live, etc. Concentrate on the development of the story instead of trying to regal your readers with all the details of your fantastical world or universe. They won't care. If you don't have a good story, you don't have anything. (Note that you CAN create your world and universe and it might actually help your story flow more easily, but don't stick it in your story. Use it for reference only.)
- Be specific and offer no more information then you absolutely have to. If you are describing a new character to the story, describe the basics. If it's not pivotal to the story to know who she is married to or friends with, leave it out.