The most common cause of the chapped lips is that the lips are lacking in moisture. There are other reasons by which the lips can be chapped or cracked but lack of moisture is the prime reason for the cracked lips.
Now to prevent this lack of moisture the best thing that you can do is drink lots of water. This will mean that you at least have 8 glasses of water daily.
Another common thing that most of us do is to lick the lips. This may provide instant drying but the fact is that it will never be long term thing. In fact in longer term licking of lips will lead to dryness and chapped lips.
Exposure to sun can cause chapped lips. Therefore it is essential that when you have chapped lips that you avoid sun exposure and keep the lip balm handy. The lip balm that you use should have the sunscreen protection as well.
Sleeping with your mouth open also causes the lips to be dry as your breath will make them dry. Apply the petroleum jelly before going to sleep so that the lips are not dry.
If your home does not have a humidified then it makes sense to have a humidifier as then you will have enough moisture at home. Also while applying lipstick make sure that you have the best moisturizing lipstick rather than the regular lipstick.
Then for taking care of lips always use the lip exfoliation techniques. There are a variety of ways in which you can do the lip exfoliation at home. The simple and the most effective method is to apply the sugar on your lips and then keep it there for some time. Once the sugar has been applied then make sure that you rinse it. After rinsing the flakes would have come off and then you can apply lip balm. You can read about best lip balm for chapped lips and also about best lip conditioner.
Even margarine or simple oil can moisten the lips and prevent it from cracking.
There are other causes of the chapped lips and these are smoking and lack of Vitamin A, B and C in the body. In fact smoking can cause lot of other problems in the lips so make sure to avoid smoking.