A sociological study is a scientific study of a certain aspect of social reality. Being a science, the scientific method is used, but the sequence might be a little bit different from the scientific method followed in the natural sciences. Basically, in sociology, there are two types of methodology being used in doing a study quantitative and qualitative.
For quantitative researches survey, experimental set-ups, polls
For qualitative researches interview, focus group discussion, participant observation, content analysis
Out of these methods, one can produce tabulations, tables and graphs (quantitative), or narratives and life histories (qualitative).
A sociologist is often interested in looking at the "taken-for-granted realities" of everyday life that people take as a given.