I wonder how long it will take for the community to finally learn that bringing a project to production stage is not an achievement. Rather, keeping that project maintenained and supported is.
See http://wakkawiki.com as an example: Programmer "proofed" that he could do, did, and.. faded away afterwards to face other challenges. Of course it's a personal project, and it's open source, but leaving behind a void is not nice. Sure, everyone is grateful for the programmer's time and code, and he is not obliged to do anything, but.. I think this behaviour is still a problem with the Open Source movement.
And yes, it's a bit controverse what I stated, but recently, for example, I had a nice talk with an OpenGroupware.org representative at LinuxTag. She told me that many Open Source developers still start their talk with something like "Hello, I'm Mike, I'm 27 years old, married, two children". I have to agree: That's not the way to address people who have to rely on what you're doing. We don't have to wonder about the fact that non-OSS still has the best standing among conservative companies.
So, generally speaking:
1) Be reliable. Show that others, that companies can trust you. 2) Be serious. Adept to the level others - they - expect. You don't have to wear a tie, but show them you're serious about them and yourself. 3) Listen to what their problems are. ("Well, if we can't SPEND money on that, we can't get it through." -- "Hm, I see the problem, what about a support contract? Software's for free, the support contract helps you to spend your money.")