A series of sentences developing into a short piece of writing on a given topic is called a paragraph. Paragraph writing is the foundation of all essay writing, whether the form is expository, persuasive, narrative, or creative.
A paragraph includes a topic sentence that introduces the main idea and acts as a starting point to expand the idea. After the topic sentence, we have the supporting sentence which supports the main idea and gives a detailed description of this idea and develops the theme of the paragraph. Finally, the concluding sentence clinches the points made in the paragraph and summarizes it by providing a logical closure to the paragraph.
The four elements essential to good paragraph writing are: unity, order, coherence and completeness. Let your opening sentence be the key sentence. It should express what you are going to write about. Every sentence in a paragraph should support the main idea expressed in the topic sentence. One should stick to the point to give a coherent effect to the paragraph. Vary the length and structures of your sentences to avoid monotony. Wind up your paragraph with something interesting. The last line could be the most impressive one.