In some ways you are very lucky because your experience of high school, hobbies and life experience will already be different from many UK/ home students so you should take advantage of this in your personal statement. But you also need to make 2 things very clear. Firstly, why do you want to study in the UK and secondly, you need to show that your English is of a good standard (usually IELTS 6ǌ or above). It is no good having IELTS 6Ǒ if you personal statement is full of grammar and spelling mistakes. But DO NOT pay for someone to write your personal statement for you on one of the many websites offering this service. If you have IELTS 6Ǒ, you do not have perfect native speaker style English and universities may reject your application if they suspect it is not your writing.
But you've got to sound: Like you care a lot, and like you're completely devoted to it. An example: "I am completely devoted to medicine for the rest of my life. It's everything for me because it's the only thing that's going to allow me to express who I am personally and professionally." High_impact language has this very strong absolute, emotionally rich, concrete side to it where as a reader I am completely engrossed, engaged, enmeshed. I buy it. I believe you. Some of the best places to look for this kind of writing is where there is someone who is making a very impassioned speech. One of the best places that I know is in the most powerful, compelling, moving speeches of our time. Like Martin Luther King's "I Have A Dream," or speeches by Gandhi, or speeches by John F. Kennedy, or speeches by Barack Obama. Speeches that really elevate you and make you feel that there's hope for you, hope for us and that there's something bigger to strive for.