Your introduction should not give away everything that you are going to be talking about. It should give some basic ideas, but please be sure not to begin your argument right then and there. A good way to make it better, is to not let the audience know what side you are on until the very last sentence. I doubt that your teacher will take off points for not following this, but it will make your paper better!
You can also do this by making your introduction, JUST your introduction. Don't mention papers just yet. For example:
Whether it's on television, paper, or simply on your phone, the news is unavoidable to the average person. Even on social media sights, articles will appear in random feed...
^Continue to talk about the news, and then go into fake news.
...Fake news is a phenomena where the media creates articles with false information. (blah blah, speak more about it, etc)
As your thesis is explaining how fake news is manipulation, that should be your very last sentence.
Also, do keep in mind, that many authors actually write their papers backwards! So, you can write your body paragraphs/explanations first, and THEN do your introduction at the end.
I really do hope this helps, and please feel free to ask questions!