In this sentence :
"You also learn what it takes to make money: a lot of effort.”
The main verb is "learn". The verb Takes is also a verb but since it is within the next clause and it is the verb of the Cataphoric refrence "it" such verb cannot be considered the main verb of the sentence.
So your final aswer is Learn.
The correct sentence should be, "Have you read A Good Scent From A Strange Mountain (The book title should be either underlined or italicized. I prefer italicize though) by Robert Olen Butler?
