These words belong to different categories: advice is a noun, while advise is a verb. When you hear these two words without context, it would be really difficult to decide which is which. Fortunately, the pronunciation helps us: advice is pronounced with an [s], whereas advise is pronounced with a [z]. Use-use is the example of the same phenomenon. So advice refers to recommendation, while advise means the act of giving advice. It is important to note that advice is uncountable.
