Try to the guidelines set by your country on ethical conduct on research.

For instance, here in the Philippines we have the National Ethics Committee (NEC) and the Philippine Health Research Ethics Board (PHREB) that ensure that all biomedical researches are conducted ethically.

A set of guidelines was published (although I believe they are going to update it by the end of this year) which health researchers follow.

Research Institutions are also being trained to have their own Ethics Committees to help the national bodies with evaluating researches around the country.

So to answer your question,

• Look out for the Ethics agency of your country. Learn if they've passed ethics guidelines which you can use to evaluate/assess your own research by.
• Find a third-party ethics evaluating body (like the ethics committees i mentioned) that can appraise your research independently and without bias.

One of the ethical issues with qualitative research is small sample size and confidentiality. Sometimes descriptions of the sample may inadvertently let people reading your work figure out who may be participants in your research. I agree with Professor Acosta who already responded that many countries have ethical frameworks and guidelines to assist you in dealing with these and other problems. Additionally, there is a body of literature on qualitative research to guide you. One issue is not to promise people anonymity when you cannot guarantee that you can keep their identities anonymous. Informed consent should include understanding the risks for the participants in the research.

See:

Wassenaar, D.R., & Mamotte, N. (2012). Ethical issues and ethics reviews in social science research. In M. Leach, M. Stevens, G. Lindsay, A. Ferrero, & Y. Korkut (Eds.) The Oxford handbook of international psychological ethics (pp. 268- 282). New York: Oxford.