One of the most valuable sites on the internet for adventure writing, actually almost any writing, is tvtropes.org . While tropes are often something to be avoided, or at least subverted, in fiction writing, they can be very valuable in adventure writing. The value of tropes is even higher in a convention setting. They are a shared vocabulary and shorthand that you can leverage to get your players on board with the setting.
Getting players on board with the setting can be one of the most challenging parts of preparing and running an adventure, especially at a convention. Setting presents problems for gamemasters that writers do not have. A writer has the luxury of exploring his setting, revealing the rules of his universe as he goes. A writer knows what parts of the setting his characters, and thus the readers, are going to interact with and can provide the reader with the necessary rules and background. Furthermore, readers never do anything unexpected, they either keep reading or put your book down. Players can, and do, almost anything at any time. A gamemaster has to establish the basic feel and rules (other than mechanical game rules) of his world quickly and clearly or risk confusion. Many RPGs are set in a fantasy or science fiction world, this means that players cannot rely on their knowledge of the real world to tell them what is possible. This can be an even bigger problem if you have a player that is "genre deaf".
We have all had the genre deaf player at one point. He is the guy who does not have a very broad knowledge of the style of world you are running. He may not realize that just because there was a Genesis Device in Star Trek II, such a device may not make sense in your Traveller game. He may want a lightsaber in every science fiction setting, or he may want to play a blond, elf archer in every fantasy game. You need to be sure that you send him clear signals about what is, and is not, possible in your world. A good knowledge of the genre tropes can help you with this.
If you spend a bit of time researching the tropes that are common in your genre on tvtropes, you can develop an appreciation of what expectations they set for your audience. The site usually has a list of what tropes are commonly found in connection with each other. There is a good chance that if you put lightsabers in your game, your players will be expecting some kind of Force-like power to go along with it. This connection is obvious, but many are not. A little bit of research will help you determine what kinds of signals about your setting you are sending your players without even realizing it. This gives you a chance to clearly rule out certain tropes that you will not be using, but your players may be expecting. You can also work backwards.
The site also has a list of places that each trope is found. Spend some time with this list and, especially for a convention game, figure out where your players are likely to have been exposed. Exposure from a film is probably more likely than from literature. If a trope you are using is present in a popular movie, check and see what other tropes were present in that movie, and decide if you need to head any of them off at the pass. You can also select a movie or book with a feel you want to emulate and see what tropes were used in that story.
Obviously you do not want to become a slave to the tropes. But, especially with a new group, you should probably limit your deviations from them. You have a limited amount of time to explain your setting before you have to let your players act (for me 5 minutes is too long). You want to be able to communicate to them what kinds of actions will be appropriate, and give them the tools necessary to fill in your descriptive blanks. Are short, mining, dwarves horribly cliched? Yes, but if you sit down for a D&D game, it is something you do not need to explain to your players. You should have unexpected things in your games, and you should subvert tropes in ways that are interesting and memorable, but you need to have enough grounding in the expected that players feel confident in acting.