This self-study of activities as a practicum supervisor in several secondary schools focuses on the supervisor's contribution to the quality of a teacher candidate's professional learning in the context of a familiar tension between on-campus courses and in-school practicum experiences. Data from both formal and informal supervisory experiences are taken from notes recorded in classes with those supervised formally, records of notes taken in practicum observations, and email messages exchanged with teacher candidates about their supervision experiences. Analysis of formal supervision experiences generated a series of insights into candidates' experiences of the practicum, a modest innovation in supervisory practice, and important reminders arising from a significant error in personal practice as a supervisor. Informal supervision experiences involved visits arising from invitations to observe extended by candidates in the author's physics methods course. These experiences generated opportunities to test an alternative supervisory strategy focused on candidates' perceptions of their learning from experience. Related literature includes the topics of learning from experience, reflective practice, and the potential significance of an epistemology of practice. In closing, attention is given to trustworthiness, the personal significance of the study and connections to the teacher education literature.