One mistake that newbies make is, failing to search the forum to see if the thread they want to begin is already existing. Additionally, some newbies don't read responses on a thread before making up theirs, which may lead to similar ideas or offkey ideas co-existing in a thread. The things you listed on this thread, OP, are all good, but has been stressed alot in the forum; plagiarism, quality content, etc. Yet newbies fall prey to such rules and get panalized.
Newbies also fail to scrutinize the forum before participating in this forum. Notwithstanding that they're rules controlling this forum, which newbies are advised to read. Yet things like quarrels, misunderstanding, fights and indept arguments happen in the forum too, which newbies are expected not to be a part of such disputes with fellow members. So, if a newbie scouts the forum and understand it fully well, they won't have issue with plagiarism and quality contents, i.e seeing for themselves how members are panalized for such mistakes, how members fight against a particular member who drops offkey responses on a thread and how members beg DT members to please remove the negative trust issued to them. Such experience would not only erect a newbies behavior in the forum, it'll make him to be careful with their contents while on the forum, thereby previewing before they publish.