Never beimpulsivein taking decisions.

Impulsive : acting or done without forethought.
Considerable : notably large in size, amount, or extent.
Cunning : having or showing skill in achieving one's ends by deceit or evasion.
Clever : quick to understand, learn, and devise or apply ideas; intelligent.
cautious : (of a person) careful to avoid potential problems or dangers.
Antonym of Impulsive is Cautious