Ask about the ratio of staff to children and make sure it falls within the guidelines set forth in your area. These guidelines can be found online or by contacting the licensing body for child care centers in your location. The American Academy of Pediatrics also publishes a recommended guideline.
All child care service providers should have some kind of early childhood development training, first aide training and emergency procedures training. Ask to see the current license for the child care center which will indicate that all staff is trained as required by the licensing body for that area.