Determine the positionality of the author. Positionality refers to the author's perspective in relation to the community or area she is studying. This should be clearly stated in the paper; however, if it is not, look for an author's biography to determine if she is writing as insider or outsider. If she is an insider, she should be upfront about this and explain whether it has influenced the work at all.
Review the research methods section of the paper or look for a description of methods. Unlike quantitative research, many people don't clearly write up their methods for qualitative research. The section should include what techniques and theories were used, how information was gathered and recorded, what philosophical paradigm the author is using and how subjects were chosen.
Analyze the level of participation of the subject group. Participatory Action Research, feminist epistemology, ethnographic and narrative methodologies usually need input from the people being studied. This could be as narrow as a review of methods or a focus group, or it could entail a detailed back and forth with the researcher and subjects.
Review the questions asked of the interview subjects. The majority of questions should be open-ended --- requiring more than a yes or no answer --- and should be framed in a neutral manner. The interviewer shouldn't inject her own beliefs into the phrasing of the questions but pull the subject's beliefs.
Assess the sampling size and methods. A good research report will list how many people were interviewed and how they were chosen. Due to the intensive nature of qualitative methods, the sampling size is likely not going to be large. The way subjects were selected is more important to issues of neutrality.
Review the results. Good qualitative methods draw logical results that stems from the research. Unlike research based on the scientific method, which seeks to prove a specific theory, qualitative methods often draw theory from the results. This is known as grounded theory.