The best way to show interest in a college is to actually be interested.
Looking up the names of a few professors just so you can mention their courses in your application essay isn’t real interest. That’s feigned interest.
You can’t fake real interest. Real interest comes from doing your college soul searching, finding the schools that fit you the best, and taking the time to investigate what it would be like to live and learn there for four years. Real interest goes beyond whether or not the school is prestigious. And real interest starts during the search, not when filling out your application.
If you don’t have a good answer to the “Why this school?” question, the solution might be to pick a different school, not to hunt for facts to help you appear more interested.