Don’t drop names. Ever. Don’t act like you’re only interested in making films that get into Sundance or Cannes when none of your films have, and mostly likely never will. Even if you have had a film play Sundance or Cannes, be humble about it. Because I pretty much guarantee the average person, hell, the average filmmaker, has never seen your film.
Don’t talk about who you know, who you’ve worked with, what festivals your film has played, what actors or actresses you’ve bedded down, what overpriced gear you’ve man-handled, unless someone specifically asks. Because if you just bring it up out of nowhere, you come across like a major douche. Especially if you’re criticizing some other filmmaker for the festival they just got accepted into, or the budget camera they proudly own, or their cute girlfriend/boyfriend who isn’t a household name.
Are there exceptions, sure. Your name is Woody Allen, or Steven Soderbergh, or…well, you get the picture. But if you’re just making your first film, or perhaps have a short or two under your belt…even if you have an indie feature or two under your belt, shut the fuck up, go work on your next script, and add something worthwhile to your imdb credits, all the while thanking the filmmaking gods there isn’t a douchebag category on that site.