What can I do to make my personal statement stand out to Oxbridge universities?

First of all, remember that your personal statement is going to go to ALL your university choices, not just Oxford or Cambridge. Therefore, definitely do make your personal statement Oxbridge specific.

What Oxford and Cambridge want are students who have a genuine passion for their subject. This means that 90% of your personal statement needs to be academically based in your chosen degree subject. In this 90% you can show that passion in a number of ways: talking about a certain module at school/college that you found particularly interesting and preferably how you then developed this by researching further; what work experience you have done in your field; what books or journals you have read on the subject; what lectures you have attended; and just generally explaining what sparks your interest in the subject.

Finally, it is vital to SHOW not TELL. This means do not list out all the companies that you have done work experience for; instead, pick a few specific examples of what you saw and what you learnt.