How to improve word choice in a college essay

RReaders in Stanford's admissions office move through essays at speed, and most sentences pass without leaving a mark. Take one any applicant might write: the moon was bright in the pitch black sky, with a few clouds around it. Nothing is wrong with it, and nobody will remember it. 'Pitch black' has been used so often that no one hears it anymore; pitch, for the record, is the sticky black residue of distilling tar, and the writer almost certainly did not have it in mind.

Compare: the moon was sewn into the sky that night, and clouds were stitched around it. The second sentence is no fancier than the first, and most students would be surprised by how it got that way.