第一段概括写出写信的大致内容:I am writing here to provide some advice to improve......\You have asked me for my advice concerning/with regard to......
第二段详述具体的建议,可分条阐述:To begin with,......Besides,......Moreover,......
第三段总结段:I hope you will find these suggestions useful and I would be ready to discuss this matter with you to further details. I am looking forward to your reply and wish you a good work.