Which themes/subjects should I evoke in a personal statement paragraph?

Having chosen your subject, you want to use the personal statement as an opportunity to show why this specific courseis a good fit for you(youre writing for five courses, I know, feels like it’s five times harder but it’s not!). This means that you want to evoke and critically discuss which areas pushed you to this field. But be original about it, make it personal rather than outlining pure theory, which the teachers will know more than you do. 
Each paragraph should have a topic sentence (main idea) and examples to illustrate. You can illustrate from theory, practical observations or even more niche aspects of the course: aim at sharing what stimulates YOU in this subject. For example a more specific aspect of a course, were it history, could be the question of WRITING history and the role of words. For example you can consider the death of King Louis XVI in France, a precursor to the French Revolution, the wording of the event itself is interesting, from “assassination” to “death penalty” or “execution”, words have meaning and impact the way we approach historical events, they can direct to a biased stance. You should use these examples to extrapolate ideas that highlight your motivation. Try to link them to other personal observations and your own experience (a trip, a school project). This shows that you understand the subject well enough to apply a certain idea to an observation of your own.