What to Look for in a Classroom is a nice chart developed by Alfie Kohn.
It lists “Good Signs” and “Possible Reasons To Worry” for a number of categories, including furniture, “on the walls,” sounds, etc.
It wouldn’t necessarily take it all as “gospel” (and nor do I believe he intended it to be). I’m not a big advocate of students seated around tables, for example. But it’s a good general guide to use and figure out which side do you tend to be on…