NAVIGATE OFF-TRAIL

Step 1: Adjust for declination
Declination is simply the difference between magnetic north (where the compass needle points) and true north (the North Pole, and the direction maps are oriented). To navigate accurately, just check the margin of your map for the declination (12 degrees east, for instance) and adjust your compass accordingly (most have a simple dial). No dial? No problem. If the declination is east, subtract the degrees from the magnetic north bearing to get the true bearing; if it's west, add the degrees (easy mnemonic device: East is least, west is best).

Step 2: Orient your map
Lay the straight edge of your compass on the map so that its true north bearing is parallel to the map's true north grid lines. Rotate the map and compass together until the compass points due north.

Step 3: Take a bearing
Let's say your destination is a spectacular lakeside campsite two miles off the beaten path. You can see it on your map–but not from the trail. To get there, lay the straight edge of your compass base plate on the map so it connects your present location with the lake. Turn the compass housing until its meridian lines match the north-south lines on the map (make sure the arrow is pointing to the top of the map, or you'll be 180 degrees off). The direction indicated at the compass's direction of travel arrow is the route you need to take to reach the lake.

Step 4: Navigate around obstacles
In the real world, obstacles like canyons and cliffs can get in the way of your straight line bearing. Here's how to go around without getting off track: With your compass in hand, sight an object–like a tree or boulder–that is beyond the obstacle and lies on the straight line to your destination. Hike to that object by the easiest route, then resume traveling along your original bearing.
From : Backpacker Magazine