Paragraphs achieve coherence if the following exist:
1. All sentences in the paragraph support the topic sentence.
2. The ideas are arranged in an order that best fits the subject.
3. The writer uses linking words or phrases (transitions) between sentences to help the reader understand how the sentences are related.
4. The writer repeats key words and structures within the paragraph to connect the ideas within all sentences.
Example of a Coherent Paragraph
Heroes perform valiant acts, and their actions positively influence society. For example, the first U.S. President, George Washington, agreed to act as president during a time when America needed a role model for a great leader. He led the country with honor and high standards. Some heroes do extraordinary deeds in a time of crisis, and they earn the recognition for their nobility. The soldiers that fight in Afghanistan work under extremely harsh physical conditions and they earn medals for their bravery. Some individuals are capable of heroism on a daily basis for helping the society, such as doctors and nurses. Heroes can rise from any level of society, but they always makes a great contribution to improve their communities.
Note how all sentences in this paragraph relate to the topic sentence about heroes, and the ideas of the paragraph are logically arranged. The writer has also used linking words such as "for example," and the author has repeated the key word "heroes" often to keep the reader focused on the topic of the paragraph.