Please, just spend 5 mins to help me, dear, while you are waiting for a cup of coffee. Thank you @-@

Today It rained. and the weather was cool in Vietnam. I went to the Highlands coffee shop and wrote this writing. Can you help me to correct it? and I would appreciate your help. Hope to get a chance to drink coffee with you here *-*

You work in a busy but poorly organized office and you are keen to be promoted. Your employer needs to find a new supervisor for your department.
Write a letter to your employer. In the letter
• Ask to be considered for this job
• Explain why you would be a suitable candidate
• Outline the current problems and changes you would like to make

Dear Mr. Smith,
I really appreciate value the time that I’ve been working here at our advertising company and I’ve learnt gained a lot of experience in whilst running several important projects. As I you know, our company is now recruiting for athe  supervisor position because I which was announced in at the staff meeting this morning.
Therefore, I’m writing this Email to apply for this position as I believe I’m a suitable candidate because of following reasons. Firstly, I’ve been working in the marketing area for 5 years from the since time I graduated from my university and I have experience of marketing operations from the stage of design stage to the final stage of packaging. ParticularlyIn particular, I have good practical skills and have succeeded in leading some advertising campaigns as a sub-leader. Secondly, I get on very well with my colleges and am good at managing real projects.
There are some current problems that I want to mention in this Email and also to offer my suggestions to improve for improving them because I want to make our projects done run efficiently. The first thing is that our projects are too large to be finished on time because we lack the number of programmers. I suggest that we should open night shifts for employees who are willing to work overtime. This will result in not only thean increase of in our employee’s income but also the in on-time projects so wewhich will gain us the credibility of with our customers. Last but not least, I think, to encourage our employees to work productively, we should implement some rewarding policies such as: promotions, holidays and commissions, etc.
Thanks for considering my Email. I’m looking forward to hearing from you. I hope my application will be accepted.
Yours faithfully!
Bao Vi

Good work Bao Vi! A few small mistakes, very easy to read.

Hi Bao Vi, I wrote you just some ideas, suggestions to consider. I'm not a native speaker so you could find some mistakes in my corrections. take care! Hope you'll find it useful. Ciao

Please, just spend 5 mins to help me, dear, while you are waiting for a cup of coffee. Thank you @-@

Today It rained. and the weather was cool in Vietnam. I went to the Highlands coffee shop and wrote this writing. Help me to correct this for me and I'll appreciate your help. Hope to get a change to drink coffee with you here *-*     * get back your favour offering you ...

to get changed i think is more related to your clothes when you want to change them and put on something else. 

You work in a busy but poorly organized office and you are keen to be promoted. Your employer needs to find a new supervisor for your department.
Write a letter to your employer. In the letter
• Ask to be considered for this job
• Explain why you would be a suitable candidate
• Outline the current problems and changes you would like to make

Dear Mr. Smith,
I really appreciate the time I’ve been working in our advertising company and I’ve learnt (gained) a lot of experience in running several important projects. As I know, our company is recruiting a supervisor because It was announced in the staff meeting this morning.
Therefore, I’m writing this Email to apply for this position as I believe I’m a suitable candidate and the following are some reasons that you could take in consideration *I changed this part cause it sounds a bit strange to me, so I wrote something that might be useful if you want to change the sentence. Firstly, I’ve been working in the marketing area for 5 years since  I graduated from my university and I have experience of marketing operations from the stage of design to the final stage of packaging. Particularly, I have good practical skills and succeeded in leading some advertising campaigns as a sub-leader. Secondly, I get on very well with my colleagues and am good at managing real projects.
There are some current problems that I want to mention in this Email and my suggestions to improve them because I want to make our projects done efficiently * to achieve our objectives efficiently. The first thing is that our projects are too large to be finished on time because we lack the number of programmers *there is a lack of programmers. I suggest that we should open *give permission to do or give them the opportunity to night shifts for employees who are willing to work overtime. This will result in not only the increase *increasing of our employee’s income but also the in-time projects so we will gain the credibility of our customers. Last but not least, I think, to encourage our employees to work productively, we should implement some rewarding policies such as: promotions, holidays and commissions, etc.
Thanks for considering my Email. I’m looking forward to hearing from you. I hope my application will be accepted.
Yours faithfully!
Bao Vi

Please, just spend 5 mins to help me, dear, while you are waiting for a cup of coffee. Thank you @-@

Today It rained. and the weather was cool in Vietnam. I went to Highlands coffee shop and wrote this writing. Help me to correct this letter for me and I'll appreciate your help. Hope to get a change chance to drink coffee with you here *-*

You work in a busy but poorly organized office and you are keen to be promoted. Your employer needs to find a new supervisor for your department.
Write a letter to your employer. In the letter
• Ask to be considered for this job
• Explain why you would be a suitable candidate
• Outline the current problems and changes you would like to make

Dear Mr. Smith,
I really appreciate the time I have been working in our advertising company and I have learnt a lot of experience in from running several important projects. As I know, our company is recruiting a supervisor. because I was announced in the staff meeting this morning.
Therefore, I’m writing this email to apply for this position. as I believe that I am a suitable candidate because of the following reasons. Firstly, I have been working in the marketing area field for 5 years from the time I graduated from my university and I have accumulated experience of marketing operations from the stage of design to the final stage of packaging. Particularly, I have good practical skills and succeeded in leading some advertising campaigns as a sub-leader. Secondly, I get on very well with my colleges colleagues and I am good at managing real projects.
There are some current problems and solutions that I want to mention in this email and my suggestions to improve them because I want to make our projects done efficiently. The first thing is that our projects are too large to be finished on time because we lack the number of programmers. I suggest that we should open night shifts for employees who are willing to work overtime. This will result in not only the increase of our employee’s income but also the in-time projects so we will gain the credibility of our customers. Last but not least, I think, to encourage our employees to work productively, we should implement some rewarding policies such as: promotions, holidays and commissions, etc.
Thanks for considering my email. I am looking forward to hearing from you. I hope my application will be accepted.
Yours faithfully!
Bao Vi

Please, just spend five mins to help me, dear,* while you are waiting for a cup of coffee. Thank you @-@

Today, it rained. and the weather was cool in Vietnam. I went to Highlands coffee shop and wrote this writing. Help me to Please correct it for me, and I appreciate your help. Hope to get a chance to drink coffee with you here (someday)*-*

You work in a busy, but poorly organized office and you are keen to be promoted. Your employer needs to find a new supervisor for your department.
Write a letter to your employer. In the letter:
• Ask to be considered for this job
• Explain why you would be a suitable candidate
• Outline the current problems and changes you would like to make

Dear Mr. Smith,
I really appreciate the time I’ve been working in our advertising company and I’ve learnt a lot of experience in running several important projects. As I know, I understand that our company is recruiting a supervisor because I it was announced in the staff meeting this morning.

Therefore, I’m writing this email to apply for this position as I believe that I’m a suitable candidate because of {=for} the following reasons. Firstly, I’ve been working in the marketing area for five years, from the time I graduated from my university, and I have experience of in marketing operations from the design stage of design to the final stage of packaging. ParticularlyIn particular, I have good practical skills and succeeded in leading some advertising campaigns as a sub-leader. Secondly, I get on very well with my colleges and am good at managing real projects.

There are some current problems that I want to mention in this email and my suggestions to improve them because I want to make our projects done run efficiently. The first thing is that our projects are too large to be finished on time because we lack the number of programmers. I suggest that we should open night shifts for employees who are willing to work overtime. This will result in not only the an increase ofin our employee’s income, but also in the number of our on-time projects so we will gain the credibility of with our customers. Last(ly), {but not least}**, I think, that to encourage our employees to work productively, we should implement some several rewarding policies such as: promotions, holidays and commissions, etc.

Thanks for considering my email. I’m looking forward to hearing from you. I hope that my application will be accepted.

Yours faithfully!, 
Bao Vi

*Strangers don't really call others "dear" unless they're talking to someone much younger. It sounds condescending otherwise.

**Added "but not least" makes the tone sound informal. If removed, you need to add the "-ly" on "last".