Write a letter to apply for Memory Course

Hi! I'm Ngan and I'm from Vietnam. Sorry, my English isn't good, I am improving it. Hope someone remarks this essay below. Thanks a lot!

Boost Your Memory course

Finding it hard to remember important facts and figures? Improve your memory in 10 weeks with our Memory Course. Places are limited and the course is available for only a short time.

Applying in writing to:
In the letter
- give some background information about yourself
- explain your own problems and why you would like to do the course
- inquire about the methods used on the course
- inquire about course fees and dates.
Write at least 150 words.

Dear Sir,
Let's me introduce myself. My name is Ngan and I am a student at Kim Dong highschool. I am sixteen years old and I live in Phu Vang village which is the small village of Ben Tre City. I want to be good at English. However, I have a problem with remembering vocabulary. I learn about twenty words per day, tomorrow I just remember about seven or eight words. I do not know why reason. And this makes my studying is delayed, I took a capsule to improve my memory but it is not effective. I also tried lots of ways to enhance my memory but it is not effective as well. Fortunately, I saw your advertisement on Facebook by change, I find it can help me. I want to know on this course, using that method to improve memory. By the way, can you tell me how are fees and dates?

Faithfully,
Ngan

There's no need to apologize on this platform. English learners are more than welcome to gain more external insight on how to better their usage of the language.

Regarding your essay, I would like to point out a couple of initial flaws:
1. Your first sentence should have been "Let me introduce myself" instead of what it is now. There's no need for an apostrophe and s.

2 You should put a semi-colon between your name and the word and. If not, opt for separating the two sentences because they're independent (stand-alone) structures. The same goes for your third sentence.

3. I would suggest revising your sixth paragraph as: I learn roughly twenty words a day. However, in the next day, I find myself only remembering seven or eight of them.

4. In the sentence after that, you needed to say either "I do not know the reason why" or "I do not know what the reason is". Why cannot be utilized in the way that you had put it in the sentence because it cannot be an adjective placed before a noun.

5. In your third to the last sentence, you could have said: I am fortunate to have seen your advertisement on Facebook. I find that it can help me. You need a demonstrative pronoun (that, these, this, etc.) before introducing an it or an object.

You have a tendency to have confusing verb usage as well. For instance, you had a sentence which stated: And this makes my studying is delayed, You cannot use makes and is at the same sentence in this structure because you were already following through.

You can revise this, for instance, in two ways:
1. And this makes my studying delayed.
2. And my studying is delayed because of this.
To avoid the aforementioned issues, I suggest trying to reread fundamental punctuation, verbs and tenses, preposition, and other fundamental grammar-related guidelines.

Thank you so much, Maria!