Ability to solve complex problems .

A will to learn.

There knowledge of a vast amount of things.

Well genetics plays a role, besides that embracing reason and logic, learn to be open minded (freethinker) question "Everything" learn to accept the truth even if it goes against you own interest, try to think out side the box or social norm.

Ways to help sharpen your logic and reasoning.

1.Learn to play games "Chess", helps teach the brain to recognize patterns & techniques also helps sharpen critical thinking.

2.Learn "Science" and how and what it is, all science really but mainly learn quantum physics, astro-physics, at least the elementary version, science is key here, the more you know about how and what the universe is made of and how it works the better you become as seeing things within reason.

3.Learn "History", lots and lots of history, only with our past do we know where we are going.

4.Sub to netflix and watch all 700+ episodes of Star Trek lol. (optional)

In the world we live in, just one thing makes some one smart. How much money they have. I didn't make the rules, I just live by them.

“A poor man wise is like a sacred book that’s never read. To himself he lives, to all others seems died. This age thinks more of a gilded fool, than a thread bare saint in wisdom’s school.” Thomas Dekker

Its not really in the IQ, its all in how useful you can be to the society.

Ability to solve complex tasks by means of effectively gathering and securing information while steadily balancing multiple variables. It's often associated with the ability to adapt to and understand the causes of change in order to do most amount of work with the least amount of energy wasted. But I guess that would be to grossly neglect 'social smartness'

Their brain.

Someone's ability to learn from a given situation multiplied by their exposure to situations (minus any retention loss over time).