1) Search for duplicates before you submit a link.
2) If the submission is not from the current year, append (YEAR) at the end of the title.
3) It should be clarified that the guidelines about comments apply to linked article authors too. "Be kind. Don't be snarky." "Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith." "Please don't post shallow dismissals, especially of other people's work."
4) There's dang's own idiosyncratic, controversial, unwritten exception to "Please submit the original source", i.e., unless it's a corporate PR.
[EDIT:] Three different replies have said to append [pdf] and [video] to submissions, but that's already in the guidelines. "If you submit a video or pdf, please warn us by appending [video] or [pdf] to the title."
Around 15% or more of HN front-page submissions are to paywalled and/or general news sites.
(I've classified the latter in my analysis of historic HN front-page activity, I haven't gone through to specifically note paywalled sites.)
And tightening paywalls can have a large impact on submissions. After the New York Times strengthened its paywall in 2019, HN front-page submissions fell to about 25% of their previous level.
<>>36918251 >