How does one go about finding out who the good instructors are?
At most US institutions (and perhaps in other countries as well), the first week or two of classes are what's known as an "add/drop" period, in which you can switch from one class to another before you're "locked in" to the classes you're going to take for the semester.  This means that if there's a professor you're not sure about, you can attend a class or two with them and get a feel for whether their classroom style and their personality are compatible with your preferences.

A lot of professors don't particularly care for this approach from their students—a student who comes into the class a week late will be substantially behind, and may require special attention to get them caught up.  But it may reassure you to know that you have this option in your back pocket should you discover that one of your professors is truly awful.