common error: a weak conclusion
Your last paragraph needs to be a conclusion.
Always sum up what has already been said in your main paragraph.
Never introduce a new topic.
Start the paragraph with:To conclude, .... / To sum up, .... / In conclusion, ...../ All in all, ......
Try to link the last sentence in your conclusion back to something you have said in your introduction.
REMEMBER TO SAY WHETHER YOU AGREE OR DISAGREE.