1. Paragraph Development

2. Structure Topic Sentence Elaboration and/or supporting information
Details or evidence
Concluding
Generally 5-7 sentences in length for readability

3. Topic Sentence General statement of paragraph’s content.
Usually opening sentence.
My hometown is famous for several spectacular natural features. First, it is noted for the Wheaton River, which is quite wide and picturesque. Also, on the other side of the town is Wheaton Hill, which is unusual because of its tremendously steep slope.

4. Evaluate these as topic sentences
My hometown is famous because it is located by Wheaton River, which is quite wide, and because it is built near an unusually steep hill called Wheaton Hill.
There are two reasons why some people like to buy cars with automatic transmission and two reasons why others like cars with manual transmission.
Clouds are white.
The problem with sentence #1 is that it contains too many details. Topic sentences are general, and details should appear later in the paragraph. A better topic sentence would be like the one mentioned above, My hometown is famous for several amazing geographical features.
Sentence #2 is not appropriate as a topic sentence because it mentions two topics, not just one. Paragraphs are usually about one main thing and so their topic sentences should also be about only one main thing.
The problem with sentence #3 is that it is toogeneral. It is also very boring! Would you like to read a paragraph with this topic sentence? Most people would not.

5. Improved Versions
There are two reasons why some people like to buy cars with automatic transmission. 
AND (in a different paragraph):
There are two reasons why some people like cars with manual transmission.
The shapes of clouds are determined by various factors.

6. Developing the Topic Sentence
My hometown is famous for several spectacular natural features. First, it is noted for the Wheaton River, which is quite wide and picturesque. Also, on the other side of the town is Wheaton Hill, which is unusual because of its tremendously steep slope.
Readers likely think, What natural features make Wheaton famous?
Sentences that follow elaborate or support/explain the topic sentence.
What else is needed here?
Only 3 sentences.
Paragraphs should be 5-7 sentences long, so more details are needed here.

7. The Devil is in the Details
My hometown is famous for several spectacular natural features. First, it is noted for the Wheaton River, which is quite wide and picturesque. Also, on the other side of the town is Wheaton Hill, which is unusual because of its tremendously steep slope. The third amazing feature is the Big Old Tree. This tree stands two hundred feet tall and is probably about six hundred years old.
Now the reader knows a number of natural features that make Wheaton famous.
*The paragraph contains 5 sentences.

8. Concluding Sentence Summary statement. Topic sentence “in reverse.”
Helps to tie paragraph to next idea or point.
You can understand concluding sentences with this example: 
Consider a hamburger that you can buy at a fast-food restaurant.* 
A hamburger has a top bun (a kind of bread), meat, cheese, lettuce, and other elements in the middle of the hamburger, and a bottom bun.
Note how the top bun and the bottom bun are very similar. The top bun, in a way, is like a topic sentence, and the bottom bun is like the concluding sentence.  Both buns "hold" the meat, onions, and so on. 
Similarly, the topic sentence and concluding sentence "hold" the supporting sentences in the paragraph.  Let's see how a concluding sentence (in bold font) might look in our sample paragraph about Wheaton:

9. Concluding Sentence
My hometown is famous for several spectacular natural features. First, it is noted for the Wheaton River, which is quite wide and picturesque. Also, on the other side of the town is Wheaton Hill, which is unusual because of its tremendously steep slope. The third feature is the Big Old Tree. This tree stands two hundred feet tall and is probably about six hundred years old. These three landmarks are awe-inspiring, thus making my hometown the famous place that it is. *Now contains 6 sentences.
In a more detailed essay, you would spend more time on each feature of Wheaton.
1st para. would discuss the river.
2nd para. would discuss the hill.
3rd para. would discuss the tree.

10. Transition to Next Paragraph
The Wheaton River, which is quite wide and picturesque, is probably the best feature. Its wide banks feature beautiful hard wood trees nestled among statuesque pines. In some areas natural beaches have formed that swimmers take advantage of every summer. Oftentimes, people can be seen hiking along the shoreline enjoying the serenity as they achieve their exercise goals in breathtaking beauty. Finally, the sun setting over the west side is every bit as beautiful as any sea horizon sunset. Hence the river is the favorite of many who come to visit. People also come to see Wheaton Hill, unusual because of its tremendously steep slope. Wheaton’s terrain consists of broad, rolling hills, making Wheaton Hill stand out like an apparition in the desert…….