The key to successful signaling is contrast: sound against silence; movement against stillness; light against dark; sharp angles against curves; one color against a contrasting color.

A signal shown or sounded in threes is the international signal of distress. For example, three shots, three fires, or three flares. All of these tell someone that you need help.

There are four main types of signaling: ground, light and fire, and sound. All of these can be equally effective in different situations.

Ground signals are good when you are in an area that is not too crowded with trees or brush. This is because ground signals are intended to be seen from the air. If there are too many trees around then you'd be hard to spot.

Light and fire are good when it is hard to see the ground from above or when the only people who could help are at a lower elevation. The smoke or reflected light can go through the trees or other obstructions so you will get the rescuer's attention.

Sound is a great method of signaling when you know there are people who can help near by. If no one is around than you could whistle for hours and no one could hear your cry for help.