Geek culture is changing, and it's an exciting time to be a fan. Crowdfunding sites like Patreon and Kickstarter are fundamentally altering the way fans do business, meaning that they can produce bigger and better fan-led content than ever before--something that benefits the entire culture. Podcasts, fanzines, webcomics and small startup conventions all have some amazing opportunities open to them right now--but one side-effect of that is that the noise-to-signal ratio has never been higher. Your idea might be amazing, but getting it in front of people is harder than it looks.
For many people, the trick is actually taking some of their marketing offline. This might seem counter-intuitive, but people love to put faces to websites and a convention is the best place possible to get that done. Conventions are so big and busy, though, that even then it can be difficult to get your voice heard above the crowd--so what can you do to make damn sure your target market hears about you while they're having their jam-packed weekend of fun?
Turn everyone who seems interested into a walking advertisement for your project.
The same principle used by the biggest designer brands can work for you, too! If there's one thing convention-goers love, it's custom badges--and by having your own set made up you'll be able to ensure that everyone at the event sees your logo, name and URL. Try to come up with a memorable, eye-catching design that gets the right people wanting to know more, and if you can it's a good idea to have the same design on a t-shirt you're wearing or (if you have a stall in the dealer's hall) on an easily visible banner. Many of the people you give the badges to will wear them on their convention badge or lanyard for the whole weekend; look out for people who seem to be collecting and displaying them, and make sure they've got one of yours.
Get super involved in the social side of the convention--and let people know what you're about.
One of the best ways to get word out at a busy con is simply to tell people. Hang out in the bar, talk to people, make new friends. If you're genuinely interested and approachable, people won't mind that you've slipped in the occasional plug for your favourite project--and once they like you they're much more likely to want to check it out and offer you their support.
Give all your potential new fans something to take away with them that they'll want to look at again.
If you write a webcomic, give out a few printed editions of your best strips. If you're starting a geeky Kickstarter project, take some prototypes with you for people to play with. If you're a podcaster, make your promotional material as engaging as possible with funny quotes and clear notices of your guest stars. Conventions are so big and busy that it's easy to forget things you've heard while you're there, but if you make your giveaway something people will want to look at again they'll keep thinking of you long after they've got home to the post-con slump.