In your opening section, you should begin by describing your core motivation for desiring to enter into your chosen course of study, this will give the admissions officer an immediate sense of your passion for the subject. Beginning statements such as "Physics has always been a subject that I've been deeply curious and interested in", "Since beginning to study classical civilisation at A-level, I have been introduced to a subject which truly captures my interest and desire to understand ancient history" or "Medicine is a subject I am keen to study at degree level as I am motivated by a desire to help people and to challenge myself academically in a degree programme that interests me deeply" are all opening statements that will give an admissions officer a sense of your interest in your subject, making it easier to create links between other achievements on your personal statement and your chosen degree programme.