The first step when you write from what you read is to be sure you understand what you have read. To ensure your understanding, you should be an active reader. This means that you should read more than once with a different purpose each time, you should ask questions before, during, and after you read, and you should make notes as you read.
Once you have read actively, you will be prepared to write in a number of different ways. You will be able to summarize what you have read. That means you are accurately re-telling the author's main ideas in your own words. A summary also gives the major supporting details the author has used to support the main ideas. Once again though, summaries are written in YOUR words not the author's words.
Another method of writing about what you have read is to respond to the reading. When you respond to a reading, you pick out a particular point or idea that the author has made and then brainstorm to develop your own ideas based on the author's thought. Unlike summarizing, you are generating your own ideas based on the author's original thought.
Rather than generating a new idea, you may also choose to respond to an idea in the reading. You may agree or disagree with a point the author has made. In your writing, you will explain why you agree or disagree with that point. Once again, you are coming up with your own reasoning and your own wording in response to something you have read.
A particular type of writing you will be required to do is writing answers to essay tests. Essay test questions often ask you to read material and then either summarize the material or respond to it in a particular way. The one thing that makes essay test writing different from other writing situations is the time limit. In a testing situation you will carefully monitor your use of time and you won't put all of the polishing touches in that you would if you had unlimited time to complete the writing.
These are some of the ways you can tie the material that you read to the material you write. You will find that if you follow the advice given in this chapter that you will never be at a loss for a topic to write about.