How do you write an essay on the topic "Think of your own topic and title. Not less than 300 words."?

300 words is really not long: it’s three or four average-sized paragraphs. So it shouldn’t be too daunting. And it sounds like the teacher is looking for your creativity, so they probably won’t freak out if your grammar or spelling aren’t perfect.

Just think of something, anything, that interests you enough to write four paragraphs. It could be the latest video game, the fight you had last week with your sister, the smell of rain, even why you don’t like writing essays. Type all the things you can think to say about it on your computer, then when you’ve got it all down, save it, and then try to drag and drop the things into a sensible order where each sentence leads towards the next.

Then give it a title. A clever or jokey title is good, but if you can’t think of one, just label it “What I think about “ followed by the topic.