Include the topic, as well as your opinion, in the very first sentence. Since a paragraph is only a few sentences long, you cannot waste any time getting to the heart of the matter.
List each of your supporting facts in a different sentence. Explain how each fact supports your original stance. You should use no more than three to five facts, and write no more than two sentences for each fact.
Close the paragraph by restating your opinion, while rewording it slightly to incorporate some of the information related in the rest of the paragraph.