Highlight, take notes, and otherwise mark up articles from quality sources.
You can quote or paraphrase what you find, giving credit to the authors.
If you are looking for the specific type of article known as a case study, one easy way of finding the most useful articles is to include "case study" as one of your search terms. Note: this example limited the search to articles in which "case study" is the subject, for greater accuracy.
The "medical ethics" search within SAGE reference draws from eReference entries like this one.