Exactly. I've read maybe a dozen grad school application letters (for successful applicants) and they were all full of specific stories of great things the person did.
The admissions system I'm familiar with has admissions reviewer summarize the recommendation into a few words about the reviewers credentials and connection, and then a numberic rating which peaks at "Best in 10 years". So you'll make this information more accurate if you begin or end with a simple statement of that data. I saw sentences like "In my 28 years as a professor at X, I've only seen 3 other candidates of Y's caliber. This is based on having Y in three of my classes and as an undergraduate research assistant for two semesters."
One more thing I liked when I saw it in letters, that may not apply to you, was something like, "I'm selfishly hoping Billy will chose to stay here and do his PhD with us, but of course he deserves to make his own choice among the best options. You'd be very lucky to have him." But I wasn't actually helping with the admission decision, so I've no idea if that kind of thing helps or not.
no subject
The admissions system I'm familiar with has admissions reviewer summarize the recommendation into a few words about the reviewers credentials and connection, and then a numberic rating which peaks at "Best in 10 years". So you'll make this information more accurate if you begin or end with a simple statement of that data. I saw sentences like "In my 28 years as a professor at X, I've only seen 3 other candidates of Y's caliber. This is based on having Y in three of my classes and as an undergraduate research assistant for two semesters."
One more thing I liked when I saw it in letters, that may not apply to you, was something like, "I'm selfishly hoping Billy will chose to stay here and do his PhD with us, but of course he deserves to make his own choice among the best options. You'd be very lucky to have him." But I wasn't actually helping with the admission decision, so I've no idea if that kind of thing helps or not.