Can you please check these few sentences, please? Thank you very much in advance.

1)I let you know about our daily timetable as soon as possible.
2) I believe you could meet at the hotel every day at around 5.45 for one or two hours of conversation depending on the day.
3) We'll probably start our lessons on 5 August because I don't know at what time our train will get to Madrid on the previous day (or on 4 August).
3) As far as the program is concerned, I mainly need to work on a school book prepaparing my students for the first certificate in English.
4) I need to train my speaking skills and improve my use of phrasal verbs as well as idiomatic expressions. In other words, I need to update my knowledge of the language.
5) Have you specialized in a particular subject? Are you a qualified English teacher? How long have you been teaching for?
6) I include (? how do you say that? I'm including?) my telephone number so that you can get in touch with me as soon as I get there.

1. I will let ...

2. remove "at"

3. "on 4 August"

4. remove "train" and insert "develop"

5. remove "for"

6. "I'm including"

Sure, here are the reviewed sentences with a few corrections:

1) I will let you know about our daily timetable as soon as possible.
2) I suggest meeting at the hotel every day at around 5:45 PM for one or two hours of conversation, depending on the day.
3) We will probably start our lessons on August 5th because I am unsure of the time our train will arrive in Madrid the previous day (August 4th).
4) Regarding the program, my main focus is working on a school book to prepare my students for the First Certificate in English.
5) I need to train my speaking skills, improve my use of phrasal verbs, and familiarize myself with idiomatic expressions. In other words, I need to update my language knowledge.
6) Have you specialized in a particular subject? Are you a qualified English teacher? How long have you been teaching?
7) I am including my telephone number so that you can get in touch with me as soon as I arrive. ("I am including" is the correct phrase to use here.)

Hope this helps! Let me know if you have any other questions.