Personal statement Watch
Check this out. I've written out exactly how you should write your personal statement. It's designed for Medicine, however, it's more or less the same for every subject.
The bulk of your personal statement should be about you. Talk about your personal qualities, achievements, extra-curricular activities. Here is the space for you to sell yourself as a student!
You might find this useful: https://www.ucas.com/undergraduate/a...onal-statement