How can we decide a school is best or not?

Are the students well behaved when you observe? Do they listen attentively and follow instructions? Do their activities in the classroom teach or reinforce lessons you believe are valuable? Does the school value academics over sports? Are their arts programs--music, art, library, etc.--valued? Are the teachers experienced? Do they continue their education in their off months, many earning masters and PhD degrees? Has the principal been there for many years? (A high turnover rate in administration spells trouble.) Do the graduates go on to do great things, whether it's get into good colleges or transition smoothly into middle school?

(It's hard to be more specific when I don't know if you're looking for a great kindergarten or the best high school.)

You could visit alumni and see if theyre successful