The first sentence in each paragraph is called a topic sentence. Topic sentences:
- explain the point you're going to make in the paragraph
- are clear and concise
- link back to your argument and introduction
- build on the points made in the previous paragraphs
- when read together, summarise your argument.
If you recorded your key points in your essay plan, you've already written your topic sentences. Take your key points, write them in a single sentence and then write a paragraph discussing each one.