I suggest you browse qualitative research journals such as Qualitative Social Work: Research and Practice - this journal has articles on observation as a method that can be effectively combined with other qualitative methods.

Hello,

Try the sites above suggested by Prof Munford, but these websites might also help:

Robert Wood Johnson Foundation: Qualitative Research Guidelines Project

http://www.qualres.org/HomeObse-3594.html

Qualitative Research Methods:A Data Collector’s Field Guide - Module 2 Participant Observation

https://assessment.trinity.duke.edu/documents/ParticipantObservationFieldGuide.pdf

Saul McLeod (2015) Simple psychology: Observation methods

. . and this one from the University of Surrey:

http://libweb.surrey.ac.uk/library/skills/Introduction%20to%20Research%20and%20Managing%20Information%20Leicester/page_54.htm

. . . and these papers:

Kawulich, B. B. (2005, May). Participant observation as a data collection method. In Forum Qualitative Sozialforschung/Forum: Qualitative Social Research (Vol. 6, No. 2).

http://www.qualitative-research.net/index.php/fqs/article/view/466/996

Jamshed, S. (2014). Qualitative research method-interviewing and observation. Journal of basic and clinical pharmacy, 5(4), 87.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4194943/

Very best wishes,

Mary

Thanks a lot Mary C R Wilson and Robyn Munford 

Best 

Another good reference book on qualitative research is Patton (2015). It offers a comprehensive review of all types of qualitative research methods including different types of observation.

Patton, M.Q., 2015. Qualitative research & evaluation methods: integrating theory and practice, Fourth edition. ed. SAGE Publications, Inc, Thousand Oaks, California.

The following sources should be helpful to your topic: 

• Baker, L. M. (2006). Observation: A Complex Research Method. Library Trends, 55, 1, pp. 171-189.
• Basil, M. (2011). Use of photography and video in observational research. Qualitative Market Research: An International Journal, 14, 3, pp. 246-257.
• Becker, H. S. and Geer, B. (1957). Participant observation and interviewing: A comparison. Human organization, 16, 3, pp. 28-32.
• DeWalt, K. M., DeWalt, B. R. and Wayland, C. B. (1998). Participant Observation. In: Russell, B. (ed.) Handbook of Methods in Cultural Anthropology. Walnut Creek, California: Altamira Press, pp. 259-299.
• Grove, S. J. and Fisk, R. P. (1992). Observational Data Collection Methods for Services Marketing: An Overview. Academy of Marketing Science. Journal, 20, 3, pp. 217-224.
• Levine, H. G., Gallimore, R., Weisner, T. S. and Turner, J. L. (1980). Teaching Participant‐Observation Research Methods: A Skills‐Building Approach. Anthropology and Education Quarterly, 11, 1, pp. 38-54.

There are number of different ways that you can use observation, some of which are purely qualitative and others more quantitative.

Several of the previous remarks have referred to "participant observation" and this a key qualitative method. Alternatively, it is also possible to do "systematic observation" where your strategy is to count things.

So, you need to tell us more about your research goals and why you are considering observation as a method.

You have already received some great references! If you would like a couple other journals for information about qualitative research you can find open access articles at The Qualitative Report that could be useful. 

http://nsuworks.nova.edu/tqr/