if #1 it is accredited? and by whom?

#2 ask the school what their nationality breakdown is. This tells you something right there.

#3 If afterschool activities and sports are important to you, ask them what they offer.

But most of all, VISIT prospective schools. Apply for your top 3 or more, if you don't get into your first choice, let your children attend an alternative one (or home school) until a spot opens in where you truly want them to attend.