And the farther along in school you get, the more complex and demanding the essays will become.
It's important that you learn early on how to write effective essays that communicate clearly and accomplish specific objectives.
Multiple choice questions can be difficult to write, especially if you want students to go beyond recall of information, but the exams are easier to grade than essay or short-answer exams.
On the other hand, multiple choice exams provide less opportunity than essay or short-answer exams for you to determine how well the students can think about the course content or use the language of the discipline in responding to questions.
Don't worry or agonize over organization at this point, just create a moderately organized format for your information.
Whether you use a diagram or outline doesn't really matter.
Pretty soon you will have whittled your list down to just a few topics and then you can make a final choice. They want to make sure they have all their thoughts organized in their head before they put anything down on paper.
Creating a diagram or outline allows you to put pen to paper and start organizing your ideas.
Some people prefer and work better with the flowing structure of a diagram.
Others like the rigid and logical structure of an outline.