Dear Sir or Madam,
As a regular library user, I would like to express my sincere gratitude to you for the help you render me.
I am writing the letter in purpose of offering some conducive recommendations to upgrade the quality of your service.
Firstly, a great many students express their frustration with our library in that there are usually long lines waiting for assistance.
Secondly, since computers are used by all major libraries to streamline cataloguing, we should have access to the Internet via computers.
Lastly, I shall be much obliged to you if you could kindly replace all the outdated facilities and provide more conveniences to readers.
I hope you will find the proposals practical.
Your prompt attention to my suggestions would be highly appreciated.
Yours sincerely, Li Ming