Our most common clothing material Cotton next to skin is bad - it soaks up sweat , you remain wet, and cotton looses its insulation properties when wet. If you know that overheating is not a risk factor, use antiperspirant to reduce sweating. A good hat is a must - we lose a significant amount of heat through our head. Avoid cigarettes and diuretics such as coffee or alcohol - they shunt warm blood away from skin. Can't do complex motor functions with hands but can still walk and talk.
Skin is cool due to vasoconstriction.
Shivering not under voluntary control . As it progresses, breathing and heart rate decreases. Then the person looks dead, but is still alive. Hypothermic person can't do it. This can develop into a medical emergency.