When I was first starting to read research papers in mathematics, I got some great advice from one of my professors. He said, "Always have paper and pencil with you when you read a paper. Read a little bit and then try to write the next part yourself. Look at what is written in the paper as a sequence of hints. That's all you are going to get. You need to fill in the details yourself and if you can't do that, you have not understood the paper." Over the years, I have realized that while research mathematics is kind of an extreme case, the same actually applies to any challenging text. So here is "the method":
- Read a sentence or paragraph or however much you need to get an idea.
- Write or say to yourself what you think is going to come next.
- Start from the beginning and read through the next chunk. Compare your continuation to what actually came next.
- Go to 2