Info dumps are an especially big problem for writers of speculative fiction (fantasy, sci-fi, etc) because more often than not we’re introducing entirely new worlds, cultures, systems of magic and alternate natural laws. This requires us to communicate a very large amount of information–whereas writers of other genres can usually depend on their readers to already know many of the “rules” governing the setting.
One of the hardest parts of storytelling (especially for those of us who are all excited about these new and unique races, cultures, and technologies we’ve made up) is resisting the temptation to explain everything. While we may be very interested in the linguistic intricacies of our alien culture, the nitty-gritty details are not going to be quite as riveting to our readers. This is where we have to do the difficult job of deciding what information is vital to telling the story, and omitting things that fall outside those boundaries.
In speculative fiction, it’s a good idea to have your world thoroughly thought out before you start writing in it. This can help give your story a depth and consistency that would otherwise be absent. While your readers may not be privy to every detail (and, in fact, should not be), your stories will feel more real and cohesive if you–the writer–have those details to draw from as you write. This doesn’t mean that you need to draw up maps with exact distance ratios and plot out weather patterns–although if you like this sort of thing, please, by all means. Just don’t plop all of your notes down on your reader and expect them to absorb all of it with the same giddy excitement.
Instead, think of your information like table salt. You want to carefully sprinkle your information through the substance and action of your story. Too much in one spot can make your dinner inedible.
The dreaded info dump itself isn’t the true villain. I think what matters most is the perceived relevance of the information. The careful, even release of information throughout the action of the story is preferable because the relationship between the information and the story is immediately recognizable–while an abrupt info dump about the role of potatoes in Irish history may invite the question “Why do I care?” Even if the information is vital in later portions of the story, if a fairly solid relationship between the information and the currently progressing story cannot be drawn, you will be lucky if your information is simply skipped. An info dump close to the beginning of the story might kill it altogether.
Thick paragraphs of exposition are usually better off avoided, but the true error is giving me, the reader, cause to wonder “Why are you telling me this?