In many cases of gathering requirements, there is no substitution for actually observing the process as it happens. You will find that often the way things are done contradict what is written in process manuals. These deviations are important as they usually reveal an inefficiency in the process that the user felt the need to employ a different method. This is valuable information for process improvement!
You should be aware that at times just the fact that a process is being observed can make the user change how they usually do things. It is important to make the people being observed comfortable with why they are being observed and the objectives of the observation. Openness and honesty are important. Solicit their input and suggestions.
As with anything project related, there needs to be a plan. You can make a simple form with elements such as:
- Process Name
- Observation date(s) and times
- Key Findings
The dates and times are important as you need to know if this is considered peak/normal/low volume time. This is a key consideration regarding the observation objectives.
After the observations are complete, you should meet with key project staff and stakeholders to discuss findings and their impact on the requirements.