“What are the practical consequences?”
Depending on what you lie about, you can go to jail. Most things you would lie about dont violate any laws, so there is no criminal activity to prosecute. However, there are certain fields where lying may constitute criminal activity. Lying to get security clearance, lying about a license in a profession where a license is required by law come to mind.
Criminal law aside. If you lie to obtain a job, and your employer finds out, you lose all legal protection from the laws that cover an employer/employee relaitonship. You will be fired for cause, which means you dont collect unemployment and you will likely not have an easy time getting another job, unless you lie yet again to your next employer.
Criminal and civil law aside, as soon as you lie, you violate the torahs command of midvar sheker tirchak.