If people think about what they’re doing, the problems can be significantly reduced.
If you post and your post doesn’t show up right away, DO NOT keep hitting the “Post” button. That causes multiple posts.
If you post, always check the “I have already previewed...” box, and don’t worry about previewing.
If you haven’t already done so, reduce your posts-per-page setting to 20.
Resist the temptation to continually refresh the page you’re viewing to see new posts. Chill out and wait a bit, let other users have a chance.
Resist the temptation to post useless, information-free comments, or comments that essentially repeat what others have said.
Also, resist the temptation to continually repost noise from Twitter. If someone is interested, they are free to go there on their own.