Observational methods are simply a way to document what you are seeing in the field. From above. From afar. Or close up.
What you measure is up to you -- as is the duration of measurement.
Define it. Refine it. And go!
Ultimately, you'll create the method for recording the desired behavior over a defined period of time. See below for some examples to plan your own.
Measuring animal behavior is often done using an "ethogram", which is simply an observational checklist applied to animal behavior. It can be adapted to humans easily. Use the video for inspiration and examples that you can apply to your field.
Interested in trying it? Use the example and rubric to get you started.
Use the STROBE checklist as confirmation (download v4 pdf). STROBE stands for STrengthening the Reporting of OBservational studies in Epidemiology and is an international, collaborative of scientists aimed at improving conduct and dissemination of observational studies.
Learn more about STROBE.