Get a tour of the preschool that you are planning to have your child go to. Is the location clean, organized, sanitary and well structured? These things can be indications of what will happen when your child attends. A tour helps you to see this in person for a real experience.
Preschools have different qualifications for what they teach their children. Therefore, you should know beforehand what is taught and what is not. Ask and then compare the various curriculums of these schools to determine if they offer the right type of learning for your child.