It does happen and how you respond early will very much impact how things end.
Remain calm and don’t panic.
As obvious as this may sound, most people who become lost in the wilderness stop thinking straight and quite often make the situation worse.
Stop moving and stay put.
As soon as you realize you’re lost, stop moving. It is far easier for search and rescue personnel to locate you if you stay in one location. Generally, people who keep moving wander farther from the trail and go deeper into the backcountry.
Seek or make shelter.
Because you’ve packed your 10 Essentials, you should have everything you need to create a reasonably dry shelter. If you don’t have an emergency tarp, look for a dry area near the base of a tree or under a log. It is critically important that you stay out of the rain or snow.
Build a fire.
Fires are not only a source of heat and comfort, but can help occupy your time and mind. Being lost is not an excuse for starting a forest fire however, so be careful if you opt to build a fire.
Do everything you can to be visible from the air and the ground during the day. Use a whistle or other signalling device to help rescuers or other backcountry users to find you.