There are several antonyms for the phrase "makes a mess of." One possible antonym is "tidies up," which means to put things in order and make them clean and organized. Another antonym is "straightens out," which refers to organizing a situation or resolving a problem. A third antonym is "perfects," which means to improve or bring to a state of excellence. Other antonyms can include "manages efficiently," "handles with care," and "organizes effectively." In contrast to "making a mess of," these antonyms reflect a positive and successful approach to managing tasks, problems, and situations.