Observe how injuries are handled by instructors and students. Injuries should be ignored if minor, endured if minor and painful, and immediately treated if major.
If weapons are displayed, do they look frequently used or just for display. If you are interested in learning weapons and you see shiny nunchaku with gold colored chains or brightly painted shuriken, it probably means real weapons are not taught at the school.
Schools vary in the type of equipment and amenities they offer. Some are large and modern, and provide weight-training equipment, showers, and lockers, while others do not. Remember, students are paying for these extras; it is up to you to decide what is most important and necessary for your training. All schools should offer basic comforts, adequate equipment, and learning essentials. Depending on your location, air conditioning may be a must. A pretty school is not necessarily a highly functional school, and vice versa.