If you're standing with your shoulders open to the target, that will throw your arrows to the right for a left-handed shooter. Try standing perpendicular to the target without a bow in your hand, looking straight ahead, and then turn your head to face the target without moving your shoulders. Look down at your shoulders; that's how your shoulders should be pointed when you shoot.
Another thing to try. If you're shooting with a straight bow arm, it can recoil to the right (for a LH shooter) throwing your shots off to the right. With a slightly bent bow arm, it tends to recoil forward.