The field note data related to a case study on AI engineering practices. During the case study, an autonomous stock trading system was developed, while 10 AI engineering practices were applied. We used field notes to document the application of each practice. Additionally, we documented any challenges we experienced. field-notes-practices.csv: the documented experiences with the AI engineering practices containing the name of the practice, the perceived effectiveness of the practice on an ordinal scale (--, -, 0, +, ++), a description of how it was applied and its effects, and the date when it was applied (in DD.MM.YYYY format). field-notes-challenges.csv: the documented challenges experiences during the case study containing the date (in DD.MM.YYYY format), a description of the challenge, the source that made us became aware of the challenge, the solution we used to overcome the challenge, and a description of the frequency of occurrence.