Every paragraph should have a topic sentence (much like the thesis statement of a paper) that states the main idea of the paragraph. The topic sentence usually, but not always, comes at the beginning of the paragraph.
All the information in a paragraph should relate to the unifying thought of the topic sentence.
A successful paragraph develops its main idea by presenting enough details to prove the point.
Paragraphs vary in length but a good rule is it should fit into your computer screen.
A strong paragraph is coherent presenting the ideas in an orderly manner and with a clear and logical relationship of one statement to the next.
How you might organize your paragraphs
Process: paragraphs structured in chronological order.
Cause/Effect: paragraphs that indicate the causal relationships between things and events. Be very careful that you don't mistake coincidence with cause ("I washed my car so it rained!").
Classification: paragraphs separate the material into major categories and then distinguish between them.
Increasing importance: paragraphs that build up to the most important point.
Comparison & Contrast: paragraphs that have a detailed account of similarities and differences. Generally, the more similar things are, the more you should concentrate on the differences. Additionally, these paragraphs can be organized in two ways. You can put all the similarities in one paragraph with the differences in another and then write a section comparing the groups of similarities and differences. Another way to organize comparison and contrast papers is to show both the similarities and differences of one point within one paragraph. This tends to work well with exegetical papers.
Example: paragraphs that give specific information to support your main point.