Regarding demand, you might have noticed that two types of changes can occur.
The first is called a change in the quantity demanded, which results from a change in price. A change in the quantity demanded is illustrated by movement along the demand curve from one point to another.
The second is called a change in demand. In this case, the demand for a good or service changes not because the price of the good changes, but because something else in the market changes. These could be changes in consumer expectations; consumer preferences; the number of consumers in the market; consumer income; or the prices of related goods, which can be either complementary or substitute goods. A change in demand is illustrated by shifting the demand curve left or right.
An easy way to remember which way the demand curve shifts is this: