In 2009, the American economy began a major downturn from which, as of March 2011, it was just starting to emerge. There are many possible causes for this downturn, including poor investment, bank errors and consumer panic. A good place to start for your research would be economic magazines as well as serious critical essays written by economists before and after the downturn began. There are many news reports online and in newspapers that can be used as secondary sources. These types of sources don't usually give you strong enough arguments for your essay so use them to either find statistics or to point you to better sources.
Joseph Stalin is one of the most infamous dictators in history. His policies directly led to the deaths of millions of his own citizens. Investigate why this bloodthirsty man made it into political office. There are many potential reasons you could investigate. Investigate his personal charisma to see if it was overwhelmingly powerful. Use as many primary sources as possible. These sources would be descriptions of Stalin by those who knew him. These can be found in history books on the Russian revolution as well as in college libraries. You can also investigate any behind-the-scenes dealings he may have made to get into power, as well as promises or political policies that may have appealed to the Communist party.
Rap music has become one of the most successful types of music in the world. Examine the reasons why by finding music history books and magazines. Rolling Stone is a good magazine to explore as it has many great critical essays about music in general. Find musical history books that explore the roots of rap music. Do interviews with rap fans and ask them what they like about the music. Make sure the responses you use are the most intelligent and well articulated. Listen to hours of rap music to examine the musical structure and the delivery of the music. Understand the music as fully as possible before writing your essay.
Causal essays don't have to be about historical events. You can describe what causes different health-related problems, such as colds or cancer. Find basic information about the condition from a medical handbook or a medical website. Use this information as a guideline for more detailed investigations. Find serious medical journals that have studies of how radiation causes cancer. Quote heavily from these studies and use them to expand your arguments. Find as many causes as possible to examine. Rule them out or confirm them, if possible.