How should I structure my personal statement?

In truth, there is no fixed way to structure a personal statement. What a personal statement should do is demonstrate each of the following: a love of the subject you intend to study at university; good knowledge of that subject (e.g. if applying for French you may choose to read some 19th-century poetry); and a holistic overview of your extracurricular interests. If done successfully, a personal statement will avoid slightly improbable cliché (such as 'I have been fascinated by the Weimar Republic since the age of 3') but will demonstrate a deep understanding of what it means to study a given subject - and, crucially, a desire to do so.