There are several synonyms for the phrase "making a mess of," including "botching," "mishandling," "ruining," "screwing up," "bungling," and "fumbling." Each of these terms implies a level of incompetence or clumsiness in the way a task is performed. For example, when someone botches a project, they have failed to complete it successfully due to poor planning or execution. Similarly, when someone screws up a job, they have made a mistake that could have easily been avoided with more attention or care. Overall, these synonyms highlight the importance of being detail-oriented and thoughtful when completing any task to avoid making a mess of things.