Always having cold can mean you are allergic to cold wind etc which worsens in winter season. Avoid exposure to cold weather with proper clothing and especially covering your head and ears. Avoid cold drinks and cold food. Drink lukewarm water always. If you have only stuffed nose repeatedly, its mostly allergic only as I mentioned above. If headache accompanies the stuffed nose its mostly sinusitis. And if by cold you mean coughing out sputum which is not colorless, you need antibiotics after check up with a physician. You should improve your immunity level to tackle problems with allergy and cold. Seasonal fruits and vegetables with regular exercise will definitely boost your immunity and help you avoid infections.