Once you have written your experiential essay, you need to check the following things: grammar and spelling; style; coherence and internal logic (there should be only one idea developed throughout the essay).
If you are not sure in your proofreading competence, ask someone else to do it for you.
It is rather a form of learning which will put you in a position to be aware of more about your strengths, weaknesses, habits, etc.
And because of the fact that no one lives in isolation from the society, you also learn about your relations with other members of your society.
One learns about him/herself, one's own feelings, attitudes and values, and so forth.
The experiential essay is more special because it is focused entirely on your own experiences.
All you need to do is to formulate your topic, to recall a given experience, and to attempt at reflecting on it.
In some sense it is good that you are not required to build a theoretical framework for your essay; on the other hand, though, you are in the dark, you have to be creative, use your imagination, and at the same time be able to describe and reflect on your experience in a very logical, precisely formulated manner.
The last part deals with experimentation - from what you have learned by now (from the concrete experience), what can you do in practice? You can formulate it in short as follows: "My first day as a teacher." There is no need to say that you have to use standard English at a very high level; that means employing terminology related to the field covering your experience.
It is also important to use complex, long sentences, in order to prove you master the language and have perfect writing skills.