1. The following information is derived from
TOPIC SENTENCE
The following information is derived from
Harris, Jeanette and Ann Moseley. "Expressing Main Ideas as Topic Sentences." CONTEXTS: WRITING AND READING. 2nd ed. Boston: Houghton-Mifflin, 1989: 46.

2. TOPIC SENTENCE - 1 The Topic Sentence
Definitions, descriptions, and examples:
A topic sentence is a general statement that expresses the main idea of a paragraph.

3. TOPIC SENTENCE - 2
A paragraph is a group of sentences that develop one main idea.
The main idea is the general statement that the other sentences support or explain.
The general statement of the main idea is also called the topic sentence.

4. TOPIC SENTENCE - 3 The topic sentence has two main parts:
subject: what the paragraph is about
focus: what the paragraph is going to say about the subject.
Examples:
Most adults / find learning a foreign language difficult.
subject / focus

5. TOPIC SENTENCE - 4 Examples:
Telephones / intrude into the privacy of our daily lives.
subject / focus
Parents of teenagers / often feel unappreciated.

6. TOPIC SENTENCE 5
A topic sentence sets up one paragraph which is usually less than a page of text;
therefore, the topic sentence should be general, but not too general.
Too general: Sports are exciting.
Still too general: Watching a football game keeps me involved.
Much better: Watching the 1988 Super Bowl game between the Washington Redskins and the Denver Broncos kept me on the edge of my chair.

7. TOPIC SENTENCE - 6
General guidelines for creating effective topic sentences:
1. A topic sentence should always be a complete sentence.
2. A topic sentence should not merely state a single fact.
3. A topic sentence should be a general statement but not too broad or too vague.

8. TOPIC SENTENCE - 7 Location of the topic sentence in a paragraph
A topic sentence may come at the beginning, as the second sentence, at the end, or may be implied. In academic writing assignments, many instructors (but not all) seem to prefer that the topic sentence come at the beginning of the paragraph.