how much can you omit or embellish?

On job application or resume, how much can you omit or embellish on your employment history? Does this matter less or more when seeking employment from difference sources such as private/educational/government (fed/state/county/coty) agencies? Are they more likley to find out that you lied on job application in the government and higher up the government? Have you seen anyone get charged with perjury for lying on job application?