This website has a great little exercise for brainstorming some prose that you could modify for personal statements, application essays, or cover letters.  Why don’t you set a timer for 20 minutes and give it a try?

http://www.writing.wisc.edu/Handbook/apessay_tutorial.html

Here’s a link to one of my favorite online resources for writing personal statements: https://www.e-education.psu.edu/writingpersonalstatementsonline/p5.html

Image: Albrecht Dürer, Melancholia, 1514