I am in the middle of helping tutees prepare personal statements for their UCAS entry. These links to You Tube films may be of interest:
why statements are often rejected
Imperial College – with a summary from 33 minutes
And on Plagiarism
There is no magic bullet – every student and every university is different and there is a danger in writing an utterly formulaic response. I hope you may use these along with whatever material your schools are issuing to help you.
Good Luck!