The nature of the personal statement is that it is a single essay for several courses and unis. This is done to alleviate the burden of writing individual essays for each application but honestly makes it more difficult for students to get into all their choices. Good job UCAS. Knowing how to write an essay that will be able to get you accepted into all of your choices will save you from the anxiety of absolute rejection.
Choose Similar Courses
This is probably the easiest way to write an essay for all your applications. Choosing similar courses for all your applications will allow you to to relate to any course you are applying to. This will allow you to showcase your understanding of a certain field of study without having to compromise to accommodate the discussion of other fields of studies. However, this should only be done if you are absolutely certain that you want to pursue your education in this major. Although this is more low risk it is very consequential as you have no room to choose different types of courses when all offers have been sent. Also, it should be noted that courses on opposite ends of the spectrum are very difficult to fit into one application file so a creative mind is needed to succeed in getting admitted into all those choices.
One way this manifests is that it is possible for you to speak about a certain topic from one viewpoint. For example, when applying to chemical engineering courses in 5 different unis you can solely discuss a single topic you are interested such as the application of ammonium nitrate. This allows you to focus on this topic from the viewpoint of an aspiring chemical engineer and really establish your understanding of the course. On the other hand, if you apply for chemistry or biochemical engineering along with chemical engineering, there would be more viewpoints you would have to showcase such as the theoretical side of chemistry and the integration of biology of biochemical engineering.
Although courses are taught differently and may teach different topics, there are always a rudimentary principles that bind them all together. Discussing this will not only allow you to write an essay for all your applications but show you really do understand what you want to study.
For example, when applying to an economics course there are several key topics that you can discuss such as supply and demand. Supply and demand are concepts that you learn early on in the course and will remain a staple throughout your studies. Displaying a comprehensive understanding of supply and demand opens the door to discussion into other fields of study that use such concepts such as business management, finance and accounting and even statistics. Being able to show this correlation will be a plus point for your competitiveness and will allow you to show your thorough understanding of the field of study.