DELL XPS Battery Life

I just purchased the Dell XPS Dev edition fully loaded. I have read a number of reviews that said this configuration runs anywhere from 9-12 hours using the hidpi screen!  I am lucky to get 4 hours of use on battery. A highly portable laptop is pretty worthless with such a low battery lifetime. Is there anyone from Dell on this forum to provide advice or explain what their reviewers did in order to achieve this battery life?