What does the phrase “to trim one’s corners’ mean?

Answer 1

Nothing. To "trim one's sails" is to make sensible adjustments according to the way things turn out. This is obviously referring to sailing ships. To "cut corners" is to skimp on things, not do them properly. I think this has an earlier origin than driving too fast to take the corner of a road or race track correctly.

Answer 2

Rounding your numbers!!!