To discuss the culture of a particular locale, you can develop a number of angles. Choose only one and research it well. Unless you're writing a book, trying to discuss every aspect of a region's culture is too broad. Some subtopics include etiquette, regional foods and ways of preparing them and language and dialect. You may further narrow any one of these. For example, you might discuss wedding etiquette, holiday foods and their significance or idiomatic expressions and their roots.
Nearly all ethnic groups share a common cultural heritage. Over time, that heritage grows and changes. For example, Hungarian culture probably absorbed elements of Russian culture when Hungary was annexed by the Soviet Union. Elements of African American culture originally came from Africa, and then changed with the legacy of slavery, Jim Crow laws and freedom. In addition, regional or tribal heritages often inform a broader ethnic heritage. To write an essay about a group's culture, the author must investigate it with an open mind, abandoning personal biases.
Again, the writer of an essay on a time period's culture will have to take care not to pander to stereotypes in biased language or assumptions. Not everyone in the 1960s was a hippie, for example. What President Richard Nixon called the Silent Majority embodied a much less rebellious population, and the tension between the two groups had a profound impact on the culture of the time. The writer must look at the period's big picture.
Holidays and celebrations represent an important aspect of most cultures. Often, a celebration represents a rite or religion or both, so by necessity an essay discussing most any celebration must also discuss any relevant tangent. The writer must look at the celebration within the context of its reason.
Each of the arts represents a facet of a society's culture, and any one art's importance will vary among time periods, regions and ethnic groups. In many South American countries and Eastern European countries, for example, poetry is an important part of culture. New books of poetry sometimes hit bestseller lists in those countries. In the United States, few people pay attention to poetry. From within any one art, a writer might choose any subtopic to describe the art and why it is important to the culture or time period in question.