The key to writng a good personal statement is making yourself stand out from the rest. Universities receive thousands of applications, with the majority of students grade predications meeting the requirements. Therefore although grades are important, your personality, interests and extra curricular activities also play a huge role in your application. Try and include a variation of interests and extra curricular activities, for example even if you are a really sporty person, instead of listing all the sports you play make sure to show evidence of your academic interests as well. Do not just list the things which you have done, but relate them to your skills and attributes. For example, if you have completed the duke of edinburgh award, make sure to include what skills this has enhanced which they may be looking for, for example commitment, determination and communication skills.
One of the main things that universities look for is a student who is truly passionate about the subject which they are applying to study. So how do you demonstrate this? Show knowledge of your subject that is attained outside the classroom. Read books, visit places and institutons, and consider work expierances in industries which your degree could potentially lead you to. Studying an EPQ (extended project qualification) can be a great way to demonstrate your passion and dedication to your subject, and show many transferrable skills which the university are looking for, such as time management, critical analysis and indipendant working skills. Similarly you could consider entering an indipendant essay writing competition, these are often run by universities. If you have your heart set on a particular university, you can research particular modules or facilities which they have and talk briefly about these on your personal statement, this shows you are committed to the university.
Utilise your word count to your advantage. Other sections in the application will show things like grades, so check what information the university will already receive alongside your personal statement to avoid it being repetitive and wasting word count on something they already know. Make sure the spelling, punctuation and grammar is of the highest standard, a failure to do this shows a lack of effort and dedication.