Ask HN: What day to launch, how to get press coverage?

From what I've gathered the best time to launch is Tuesday at 10AM (pacific). Do you guys think that the day and time we launch really matters?

I'm also curious about the best way to get PR and coverage on the major blogs, even newspapers? Should we seek an embargo even if we're pitching multiple blogs? Or, should we offer an exclusive to a single blog?

Everyone says it's about developing relationships with the bloggers/journalists - but the main way people do that seems to be with tips and leaking stories. What about those of us who don't have juicy details about the next google purchase? Is simply commenting on their posts enough? And what about getting in touch with newspaper journalists? I've signed up for HARO, but what else can I do?

Any tips, advice, stories from your experience would be great. Thanks.