Whats the best way to handle multiple authors?

I’d like some advice on how to juggle multiple authors.
When I give them instructions on how to post its very confusing for them, especially when handling images.
They get confused on publishing the image, and on why it uploads as a thumbnail and not the larger picture.

Also sometimes theres a great post and I want to leave it up top but another author will post something thats not so great and it knocks down the really good post.

Anyways was just wondering if anyone had tips on how to handle and manage multiple authors.

thanks