As you sit down to produce your adventure, either in your head or at your table, one of the most important and annoying elements you must convey to your party is information. Whatever the adventure, and whatever the goal, you will have to tell your party what it is, where they can find it, what they have to look out for, why its important and who else is trying to get it ... along with many other details.
In standard D&D practice, as set out by module after module - even those produced today - the adventure includes pages and pages of important material of this kind at the beginning. And sadly, many DMs deliver this information to their players in a solid block, right at the start of the campaign. Without question this is the worst sort of storytelling, as I shall attempt to demonstrate.
Now, I hate the movie Star Wars, but since I know all the gentle readers are familiar with it, and since I am familiar with it, I shall use it as a template. The story opens with an action sequence, and after the death of a few rebels, Vader comes out and says a few words to the other soldiers about making sure they do their jobs. Then the robots ramble down the corridor, with C3PO speaking continously, running into Leia and her projection. The robots escape, hit dirtside on Tatooine and get bought by Luke and his uncle. The robots escape as a plot device to get Luke together with Kenobi and there's a conversation that happens while the robots get a bath.
This pedantic description of something you all know painfully well is here to demonstrate the practice of writing exposition. Vader's first statements to the soldiers conveys a little bit of information that you, the viewer, need to know. The robots talking in the corridor give you a little better picture, letting you know the purpose of the ship, that the captain's decisions made no sense and so on, conveying to you that there is a mystery here. Only part of the holographic works, because that's a better hook than the whole holigraphic working. Luke and his uncle chatter about things as they buy robots to give you more information about the life of this kid, and a bit later a whole waft of information is given to you by Kenobi explaining as little as possible to Luke. And of course the full holographic still doesn't tell you everything you need to know.
Unlike your standard D&D module, the information is given to you in dribs and drabs by various characters of the story. Even when Kenobi tells Luke about his father, he does not tell Luke about his father, does he? He doesn't say, "Oh, and your father is Darth, and he's probably somewhere abouts looking for us right now, so we'd better get on a starship and make it for Alderaan right now, because I've heard the Empire has a planet busting weapon and they might use it before we get there. If only we had a hot shot pilot to fly us there quickly. There's a bunch of those at Mos Eisley, I've heard about a guy with a wookie who's good - oh, wookies are huge hairy sasquatch things. Then, after we get to Alderaan we can join the rebels at Yavin and take out the Death Star - that's what they call it, don't you know - by hitting it in the exhaust vent. Well, we better get going. Don't worry, because I can control men's minds. And oh, in case I forget, if you ever get caught in the bottom of a garbage vault, there are snakes."
And yet, you will get information of this kind, in abundance, at the beginning of a D&D adventure.
The first rule of exposition is to resist telling the reader - or the party - anything that is not strictly of importance, at the moment of telling it. It is important to keep it quick, to the point and whenever possible, make it sound like it isn't exposition at all. Luke and his uncle's exchanges are fast, and depend upon the tired cliches of every kid wishing he or she could do something his or her parental figures say no to. But while it's a cliche, it's a fast cliche - it doesn't get bogged down in a lot of clever rhetoric describing just what a power converter is. Really, you don't care. The same goes with a lot of other words and references, such as 'Anchorhead' and 'the south ridge.' The only important thing that is actually said is the oblique reference to the "agreement" so that Luke can sullenly walk out and talk to C3PO and get more information from him.
If, as a DM, you scatter the information you give to your players through a dozen NPCs, signs, passages in books and so on - however cliched - the pace and excitement of your campaign is less likely to get bogged down by long readings from prepared pages. If your adventures are designed to give the information throughout the party's travels, through overheard conversations, casual observations, vague references and the occasional two-minute explanation, your party's interest in the mystery will mount from hour to hour. What's more, it increases the opportunities to give misinformation, which will reveal itself exactly as the information does, allowing all kinds of red herrings and wrong turnings. If you really want to get a party going, consider the possibilities of introducing Three's Company misunderstandings, delivered exactly in the same manner (half an overheard conversation that completely gives the party the wrong idea).
It is an error to convey every piece of information the party needs as though it comes from the voice of God, which it will seem to do if you put it in the mouths of Kings, Lords, Wizards or authority figures like Kenobi. Putting your adventure into the mouths of bawds, thieves, peasants and harlots will greatly change your party's perception of the information, making your adventure more accessible and interesting.