If you have been assigned an essay on the topic of the importance of families, your first task is to think about what sort of perspective you are being asked to write from.
In a personal essay, you would want to talk about your relationship with members of your family, and how they have supported and nurtured you. You might include specific examples of positive memories about your family and ways in which they influenced you are you were growing up. Your family not only took care of your physical needs, providing food and shelter when you were a helpless baby, but also began your education (teaching your your first words in your native language).
From an anthropological perspective, you might look at how family and kinship networks operate to create social bonds and establish social norms. Rather than focusing on anecdotes, you might write in the third person to talk about how, for example, extended families help with child rearing.
Another way to think through this issue is to imagine how life as an orphan, without either a nuclear or an extended family, would differ from life within a family.