Primary research articles typically have the same structure. The text is proceeded by an abstract, which is a summary of the article's main points. Next, there is an introduction, a methods section, a results section, and a discussion section (IMRD).
Step 1: Read the article very quickly
Step 2: Read the article thoroughly
If the article is highly relevant, you'll then want to read it all the way through. Scientific articles tend to be complex, and you may have to read it more than once. Take notes, and consider writing a brief annotation to increase your comprehension even further.