It's sad that this needs to be said, but basic hygiene and proper grooming is at all times mandatory. Other people can smell you. Please shower regularly and use deodorant, brush your teeth, change your clothes, and wash your hands now and then.
See also: Stay Healthy
Con is crowded. If you stop, so do the three dozen people behind you. If you want to go into your bag, take a picture, or chat with a friend, move to the side and keep the main walkways clear. Photography is banned in many high traffic areas for this reason. Additionally, try to be aware of how much space you take up. Your overstuffed backpack or fairy wings can take up plenty of space in a crowded walkway, such as if you stop in the dealer room to look at bootlegged anime DVDs. If you're part of a group moving more slowly than others in a tight location like the habitrails, try to go single file so that others can pass comfortably. Besides, it hides your numbers.
It is especially important to keep moving when you get to the top or bottom of the escalator you are riding on. There are no exceptions. The twenty or so people behind you will not have the option of stopping too and someone will get trampled.
Getting a space in a host hotel elevator is hard. Now imagine trying to get into an elevator in a wheelchair or scooter, crutches or a walker. Hallways are crowded, be aware of people who might need more space. Please politely move out of the way, or wait for another elevator if need be to make room. Also, it's very important to keep in mind that not all disabilities are visible ones. Asthma, diabetes, fibromyalgia, arthritis and a host of other chronic illnesses cause people problems that usually result in them needing elevators, even if they don't look it.
If someone asks you to make a space, please comply. The elevators will come back down and you'll have another chance to board.
We realize getting around in a mobility device or with other assistive technology can be difficult. We hope that in the main the DragonCon community is gracious and helpful enough to treat disabled con-goers with respect. In the excitement and heat, though, people do forget. Please try to keep even tempered when the other con-goers forget you are a human being (or Klingon or Dementor or...whatever) with just as much right to be there.
Contact con staff if you encounter any problems a polite conversation can't easily resolve.
Some people may want to pose or adjust their costumes before photographs are taken and plastered across the Internet, if they want their photo to be taken at all. Candids aren't always appreciated. Also, avoid taking photos in the crowded main walkways and travel paths. In the Marriott, traffic tends to flow towards the center. Move off to the side for photos. Posing for photos in the habitrails may get you more than a few evil stares. Cosplayers need to eat too. Avoid trying to get photos in the food court, especially if they've already removed parts of their costume so they can eat. Plus, it just means more time until that valuable table space opens up.
See also: Photography
Sure, lines get long. Sure, you want your buddies to sit near you. But having one person save a spot for two hours, and 10 minutes before the panel opens, eight more people join in? Not cool. If you plan on saving spots, at LEAST make it a 1:1 ratio of savers vs. cutters. The rest of the line will consider you a lot less of an asshole.
This is another of those "it's sad we even have to mention it" items. Just keep your hands off without approval. That includes touching costumes and glomping, celebrities and art displays in the gallery or dealers' rooms. Just because someone is cosplaying a character you love and is doing an amazing job of it doesn't give you the right to grab pieces of their costume, or grab them during a photograph.
Drinking is fun! It can also be somewhat dangerous, but even worse, it can make you a jerk. By and large the attendees of DragonCon know their limits (to say nothing of whether they pay attention to them) and aren't horrible, obnoxious drunks. But if you know yourself to fall into that archetype, please, don't overdo it. You're an annoyance to everyone around you, especially your friends. Just take it easy. Also try not to stand on furniture, and try not to run headlong into your hotel room's windows like a certain Hilton guest did at DC 2010.
Let me guess. You have written a fabulous book that everyone would love, if only they knew who you were! Or, you are convinced that if only Voltaire heard your SciFi extravaganza about Trikster Trekkers, he'd book you immediately as his opening act. You figure the best way to get your name out there is to dump hundreds of business cards and/or flyers on every table you see, including the blood donation tables (shame on you!). Well, Sara McCorkendale from Information Services asks you to keep it streamlined. I emailed her, and she said the only places you may put your material are on the freebie tables in the Sheraton. She said any cards or other materials found anywhere else will be thrown away. Market at your own risk.
Tip your waiter/waitress/bartender/bellhop/valet. It may be a con, but they still survive more on tips than on their wages. They do NOT get paid more just because several thousand people are at the convention center down the road. In addition, the presence of those thousands of con attendees is adding double, triple, maybe even quadruple their workload. They get paid the pittance they get hour in and hour out no matter how many people they serve. Tips are that important.
Too hard to work it out?
Here's Google's own tip calculator
Here's one for splitting the check.
Got an Android device? Tip calculator apps, right here.
iPhone user? One of many Tip calculator apps.
Don't like Johnny Law looking down his nose at you? Humiliating, isn't it? It's even worse when the DC staff do so. The rules are there for a reason, and that reason generally isn't to annoy you, specifically. If DC Security/Hotel Security/The Police tell you to do something or not to do something, best to do as they say in a polite and timely manner.
Find a con staffer and discuss it calmly and rationally with them. The faster you can let con staff know something is wrong, the faster they can get the message up the chain of command to correct it. Having the name and security/volunteer group of the person-in-question is extremely helpful. Large cons like SDCC may have as many as three different security companies and several dozen departments handling volunteers to run things.
This goes for both panelists and the members of the audience.
A general tip for all convention situations. Laws, common courtesy, responsible actions and behavior do not end when you walk through the doors of the convention.
Cosplay Etiquette [girlsentertainmentnetwork.com]
Presenting Sid's convention guidelines [neoengel.com]
Lycorne's Convention Tips, Tricks, and Conduct [lycorne.livejournal.com]