How would someone who is really clueless and horrible at promotion learn those kind of skills?
Part of it may come from designing the product to help with the marketing. That may also help with viral marketing.
Marketing is a pretty broad topic, and it can vary a lot, too. Maybe it's a good idea to talk to some of your customers face to face to learn more about their industry vertical. If you share some specifics, maybe more people here could suggest ideas.
Another Show HN I posted went nowhere — even though it was a good enough idea to separately get media coverage because it was timely (including in a front-page article of the NYT). There is a lot of luck involved, but you can also make your own luck, by reaching out to folks who might be interested.