I don't know how you guys handle it now, but perhaps you could be stricter about deleting/locking/merging duplicates? And maybe you could keep a permanent announcement in Hell containing some of the forum rules that aren't so apparent, such as looking before you post, the proper way to post a newspaper article, etc.
There just have been an unbelievable amount of duplicate or very similar threads, it gets to be overwhelming after a while.
And about getting lost trying to read all the new topics: I just use the "View New Posts" link at the top of every page. It's a lot easier than trying to navigate through however many boards we have now.