It's really important to understand the community that you are sharing your content with, you should have an idea of what they like and dislike. Often time rewording your post's title can make a big difference.
You should turn on "showdead" setting in your HN profile.
There is a "showdead" dropdown in your profile that you can set to "yes". Once you do that you can view new posts and see all the posts that are getting flagged or marked dead. You can learn and see what posts do well and what posts get flagged.
Might be self-explanatory for some of you, but hope it is useful for some of you!
Bonus tip: there is another view "hacker news classic" that I think filters out a lot of content from newer users (newer posts and ignores new user upvotes)