Always tell someone where you are going and when you will return.
It sounds simple, but having someone know where you are heading and when you will return is often the most overlooked step to ensuring a safe backcountry mission. Things can go wrong to even the most seasoned backcountry travelers. Having someone on the outside who knows your objective and keeping tabs on your return can shave hours or even days off a successful rescue. It is also a good idea to keep a note in your car stating where you are headed, what time you set out and when you plan on returning.
(Image provided by, State of the Backcountry)