How to read and understand a scientific paper: a guide for non-scientists

Before you begin: some general advice
Reading a scientific paper is a completely different process than reading an article about science in a blog or newspaper. Not only do you read the sections in a different order than they’re presented, but you also have to take notes, read it multiple times, and probably go look up other papers for some of the details. Reading a single paper may take you a very long time at first. Be patient with yourself. The process will go much faster as you gain experience.

http://violentmetaphors.com/2013/08/25/how-to-read-and-understand-a-scientific-paper-2/