Drinking plenty of water can be very helpful. Avoid licking your lips. It will not moisturize them, and instead will make your lips even drier.
Before going to bed, use Vaseline on lips. In the next morning, your lips will be soft and moisturized.
Choose a good quality lip balm to protect your lips. Avoid low quality lipsticks. You can use lip balm as foundation, before using a lipstick, so that your lips will look moisturized.
Avoid flavored lip balms, especially ones that have lemon, orange etc. flavored. They will irritate the lips even more.