Yesterday I launched Lucky Resume Maker on Hacker News and got to the front page! Overall it resulted in 20,000 unique page views and a few purchases. Hacker News traffic isn't targeted, so the conversion was very low, but I got a lot of valuable feedback in the comments, a few purchases, and a podcast invitation.
I don't have any advice for launching on Hacker News, or any idea why it hit the front page. I've tried Show HN's before and they never got any upvotes. Also, the moderators completely changed my title so focusing too much on your title is probably pointless.