After Castro's revolution, Cuba was no longer able to trade with the United States. This led to Cuba's over-reliance on trade with the USSR, and a Cuban economy that was even less able to diversify away from the sugar industry. Consider how this leads to Cuba's '10 million ton harvest,' which was devastating to the environment.
Consider the types of people who were likely to be dissatisfied with Castro's government. How many opponents left the country to seek asylum in places like the United States, and how did this affect Cuba's labor force?