One idea per paragraph.
In most cases, when writing about ideas, each paragraph should be devoted to exploring one single idea. (Usually you will state this idea at the beginning of the paragraph — some teachers call this a “topic sentence.”)
As much as possible, write short paragraphs, and state the main point in the first sentence or two.
Don’t:
write extremely long paragraphs. If you have an entire page without a paragraph break, the paragraph probably too long.
switch topics in the middle of a paragraph