Discuss the fact that a paragraph generally has two parts: the main idea and the details. The main idea is basically what the paragraph and all of its details are about. Offer some examples, such as "I went to Disney World on my summer vacation," "There are three states of matter," or "Fruits and vegetables are good for you."
Explain that the details are just that: specific things about the main idea. Offer an example based on one of the main ideas. For example:
"On my summer vacation I went to Disney World. My favorite ride was the teacup ride. I liked when we ate at the restaurant with Donald Duck. We had a lot of fun but it was very hot."
Help the writer get started by picking out a main idea and writing the first sentence to explain it. Ask what the writer is interested in, knows something about or has recently experienced. Help her build her first sentence from there.
For example, if she likes cats, she might start with a general sentence regarding something she knows about cats. She might, for example, know that there are more cats kept as pets in the United States than dogs. If so, she can write that down as her main idea.
Help organize or plan the paragraph. Some schools have students write an outline, but you also might use a graphic organizer, which can be any variety of webs, pictures, or bubbles. For example, draw a circle in the center of the paper and have the student write his topic sentence in it. Then draw three circles or bubbles nearby and connect them to the center with a line. In each smaller bubble, the student should jot down the gist of the detail he wants to include, not a whole sentence. For example, the paragraph on cats might have these three notes in the small bubbles: numbers, compared with dogs, history.
Have the student write at least one sentence for each small bubble. These can be as short or complex as the student is ready for. Older students can write several sentences about each detail, and sometimes this leads to writing an entire essay rather than a paragraph.
For example, for the "numbers" bubble, the student can write how many cats are kept as pets in the United States. For the "comparison with dogs" bubble, she can write how many dogs are kept as pets, and for the "history" bubble, she can write when cats were first kept as pets.