You should avoid drinking alcohol it can worsen hypothermia. Take high protein snacks to eat. Make sure to breath through your nose rather then your mouth this will reduce heat and fluid loss. If you get wet change as soon as possible,wet clothes can bring on hypothermia. Keep your back to the wind and move your fingers and toes to keep the blood flowing. Your biggest heat loss is from your head and feet so keep the warm. Keep your chest warm this will help your heart beat and keep the blood flowing to your extremities.
To check yourself for frost bite which is a soft tissue injury. Look to see if the effected area appears red then white and the skin is soft to the touch. There are 3 degrees of frostbite.