1. Pay attention to cold and warmth. In the south, the winter in Hubei, where I live, is generally around zero, but it will be colder in the north. Be sure to keep warm and put on more clothes.
Besides wearing more clothes, you should do more exercise. After work, you should jog, swim, ride a bike or play ball with friends. These exercises can increase your body's resistance and immunity.
Wear a mask when going out, and try not to go to crowded and unventilated places. Wash your hands frequently and open the window for ventilation after you go home, which can also effectively prevent you from catching the flu.