I have known [student] for [length of time] in my capacity as a [your job title] at [your employer]. If Applicable: [student] worked for me as a [job title]. or [student] belonged to the [club or organization] for which I served as an advisor. or [student] took [number] courses from me, including [names]. [Student] earned grades of [list grades], respectively, in those courses. Based on [student's] grades, along with his/her [excellent, good, etc.] attendance and class participation, I'd rate [students] performance in my class as [rating].