NOTE: You can combine keywords in a search by using AND.
Ex. observation AND ethics; "attachment theory" AND behavior.
Generating additional keywords:
You can use the names of specific theorists (ex. Piaget, Erikson) or theories (ex. attachment theory, temperament) as keywords.
Think about what factors might influence child development in your observation setting (ex. parenting style, class, race, nutrition, health etc). Incorporate those factors into your searches!