A Closer Look at the Parts
The Topic Sentence
The topic sentence tells the reader what the paragraph is about. A good topic sentence does two things: (1) it names the topic, and (2) it gives the focus or main point.
An interesting topic + a specific focus or feeling = a good topic sentence
Humans build homes (an interesting topic) but so do many other creatures (a specific focus).
The sentences in the body of the paragraph include the specific details that the reader needs to understand the topic. The following sentences include plenty of specific details.