Reading research articles--reading to understand the content and then critique it--is a learned skill.
Below are links to several articles that will walk you through the process. Whether the tutorial is titled a scientific or research paper, the processes are essentially the same. The same skills will translate to non-scientific or humanities based materials.
Mary Purugganan and Jan Hewitt: How to Read a Scientific Article (their worksheet/template is below)
Critically Reading Journal Articles