For your first paragraph talks about your subject, why you became interested in it, why you’re a good candidate to do that subject over other people.
For your second paragraph talk about all the books and blogs you’ve read, TED talks and documentaries you’ve watched, any places for instance museums that you’ve visited. Talk about how these have impacted you, what you’ve learned, why it’s relevant to your course and show that you’ve gone above and beyond in your subject because you’re genuinely interested in it.
Another paragraph should be about anything that’s made you an interesting person, what have you done to enhance yourself? E.g D of E’s completed and how it has helped develop you as a person, and what skills you’ve learnt. Any volunteering that you’ve done and why doing so has made you a more understanding person or whatever you got from doing it. Any instruments that you may play and how it’s made you committed etc. Also any work experience that you’ve done.
You should also consider writing what subjects you do right now, e.g a levels and what you’ve gained from them. Obviously it’s best for it to be related like if you want to be a dress maker having a subject like textiles could help you because you can now sew etc. You should write about all your subjects even if it doesn’t seem relevant. E.g a textiles degree isn’t relaxant perhaps for a banker, but by doing textiles you should have gained some skills such as it helped you to keep to a deadline.
It’s also a good idea to have a short conclusion saying how you understand the challenges that doing your degree may bring etc, or some sort of deeper understanding that you understand that your degree isn’t going to be hearts and flowers but you think that it will benefit you and the Uni will benefit from having you.
That’s a general kind of structure that I used because I’m genuinely interested in my subject and I think Uni’s like that. Try to keep it real, they don’t expect you to be perfect but put your best foot forwards, you can call up the uni’s and find their reading list online and just try to keep it honest, not too modest but not too in their faces.
Good luck I hope this helps!!