Of course, you must follow whatever the assignment is. But unless the assignment says so, don't make it just about "yourself" in general. Don't write a capsule biography, or a CV, or a Who's Who entry. Everybody was born, almost everybody went to school, belongs to clubs, etc. They all sound alike.
Search for something that none of your classmates can write, because they haven't had exactly the same life experience.
Make it about something slightly unusual that has happened to you, or where you've done, or where you've been, or some special point of view you have. Narrow it down. Search for _a story_ of some small part of your life, something that you would tell friends.
Find "the little picture in the big picture."
Then just jump right into the story itself. Don't introduce yourself, introduce the story. The very first words could be about the incident.
For example, "Legend has it that the road to Lick Observatory has exactly 360 turns. I didn't try to count, but when I had driven halfway up, I suddenly recognized the feeling I was starting to have. It was the first, tiny but unmistakable signs of motion sickness. And there was no place to pull off and no place to stop."
Or, "It was just some flowers somebody was growing in front of their apartment. And it was just an ordinary butterfly that landed on it. But, just for a split-second, it made me feel good. Nature doesn't exist only in national parks or unspoiled wilderness. I try to notice it and appreciate it, even if it is just some everyday thing I see on a walk in my neighborhood."
After the "hook" that introduces the story, the whole essay could just be the story of that incident. Or, having pointed out some little thing about yourself, you can zoom out to the bigger picture of you and your interests.
Here's my tip: on any "essay" assignment, it is important to write something that the teacher will find interesting. They'll forgive a lot of small mistakes if they enjoy reading what you've written.