Look, too, to see how the author switches from explaining how the evidence supports her or his argument to the summary of the paper. The conventions also require that there be some reference to the thesis statement and perhaps even an echo of the title, especially if there was a catchy phrase in it. Second thoughts should probe somewhat deeper. Thinking about what the author is trying to say, considering who he or she was addressing in the first place, attempting to identify the gap the article has been written to fill and asking other such questions is the foundation for the critical evaluation of the article. Even if you didn't know anything about the topic before you read the article, you can make some judgements about it and how well the author made her or his case.
Evaluation is a bit harder.
In academic circles, evaluation means to judge the worth, usually by comparing a thing to some kind of standard. In the case of evaluating an article, that standard would be other articles in the same discipline or journal as the one you're reading. If you are not familiar with those other articles it may be hard to evaluate well. You can, however, do a fairly good job of it by considering the stylistic and structural conventions of other, similar articles. Sometimes even those questions can be hard to answer but they should be attempted.