what affects the supply curve and what affects the demand curve
Products and services that complement what you offer the market can affect the demand curve. For example, you may sell hot dogs, while a complementary business offers hot dog rolls. If the price of the hot dog rolls increases, it can cause the demand for hot dogs to decrease.
An increase in supply is illustrated by a rightward shift of the supply curve, and, all other things equal, this will cause the equilibrium price to fall. A decrease in supply is illustrated by a leftward shift of the supply curve - this will cause the equilibrium price to rise.