Define smarter? Smarter as in having more knowledge or having more wisdom to use that knowledge?.
Knowledge is something easely gained by following school or studying things you find interesting.
Wisdom is something you slowly gain, its not something that can be tought in general. You have to take a step back and observe and be able to take in multiple perspectives on things. Only by being completely open minded will you gain more wisdom.
Forget textbooks, read autobiographies. That's where people record their views on their experiences, and all knowledge is just experience.
Ermmm.... You cant actually make yourself smarter... You can educate yourself and try to learn new things though... I suggest reading a lot. Even if its fiction there is often a lot of fact mixed in with the rest.