To add zing to something means to make it more exciting and enjoyable. Synonyms for this expression could include spicing things up, adding some pizzazz, infusing some life, making more lively, adding some spark, jazzing up, adding some flair, adding some pep, injecting some energy, throwing in some zesty, adding some flavor, livening up, adding some vibrancy, bringing some color, and invigorating. All of these synonyms have a similar meaning to adding zing, and they can be used interchangeably depending on the context and the intention of the speaker or writer.