Your resume should list projects and accomplishments, and use the application to describe responsibilities. You want to be specific enough so that by the time someone who has no idea of who you are or what you've done has finished reading your resume, they have a good idea of your capabilities, skills and accomplishments. In other words: be very specific. And when listing accomplishments or projects, make sure you state what the outcome was. So for example:
Bad: "Helped achieve operational efficiencies"
Better: "Analyzed and redesigned order fulfillment process to improve efficiency"
Best: "Analyzed and redesigned order fulfillment process, which reduced time-to-fill by 20% and achieved cost savings of $2 million.
One exception to the rule of being specific is consulting or other work where confidentiality comes into play. In those cases it's perfectly ok to hide the names of clients (e.g. Coca-Cola could become "a major multinational beverage company") or otherwise be vague so as to not violate confidentiality. Of course, if you have to be so vague that the reader won't know what you did, you may want to pick a different project to list.