You can use Le Chatelier's Principle to describe the equilibrium shift.
Le Chaterlier's Principle states that: "If a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract the change."
Thus, if you heat up the reaction, the equilibrium shift favors the endothermic reaction. If you increase pressure (if gases are involved), the shift favors the reaction that produces less gaseous products (to counteract pressure) and so on.
