Mid 2014 Macbook Pro 15' battery life

Bought the 15' Macbook Pro w/Retina display, with the advertised battery life of around 8hrs. Just getting 4hrs of normal use, no extensive tasks. 8hrs of advertised battery life should at least translate to 6hrs of real world usage. Anyone has any suggestions to extend the battery life of the laptop?

Bought it in Dec 2014, battery condition should be fine.

Thanks

Frank