First, try to determine if what you have is dry scalp. Look to see if other parts of your body are also experiencing dryness. Also look to see if small, dry flakes are present on your scalp as well.
If you find that you are truly experiencing dry scalp, try to determine the reason. For example, dry scalp can be caused by products, improper moisturizing, drying heat, cold temperatures, and even chemicals (i.e. relaxers, permanent haircolor).
Once you determine the cause, try to eliminate the cause. An example would be switching from using permanent haircolor to the use of a demi-permanent or semi-permanent haircolor.
The most common practice that causes dry hair and scalp is improperly moisturizing the hair. Clients often apply oil or butter directly to dry hair and expect it to be moist. If you are using oil or non-water based moisturizer, you will have to mist the hair with a liquid before applying your oil or butter to create moisture.