①How is everything going? I'm extremely pleased to receive your letter， from which you have asked me for my advice on how to do sth. So I’m writing to share my opinions with you.
②How is everything getting along recently？I’m more than delighted to receive your letter asking for my advice on how to do sth，so I'm writing to give you some suggestions /tips.
其中more than+adj 表示很，非常=extremely+adj,非常高级的表达； asking for my advice on how to do sth是现在分词短语做后置定语（高级结构）
③ How is everything going? Knowing /Learning that you are having difficulty in doing sth, i'm writing to give you some suggestions.
④ How are you doing these days? I'm sorry to hear that you don't know how to do sth. Here are some tips.其中that引导宾从
In the end, I will be very glad if you find my suggestions useful/ practical. Looking forward to your early reply.
The above are my suggestions, which I hope are of great use to you. Looking forward to hearing from you.其中which引导非限，句子使用了be of+adj+ 抽象名词的结构
If you follow my advice, I hold the firm belief that you will make much progress in…
I have learned with much delight that 从句，我很高兴地了解到…
It came as no surprise to me because…对我来说并不惊喜，因为
寻求建议 ask sb for advice（建议：advice、tips、suggestions）
处理 deal with/handle/cope with/tackle
遵循/接受我的建议：follow/accept/take my suggestions
向某人寻求帮助：ask sb for help、turn to sb for help
How is everything going recently? I’m more than delighted to receive your email, from which I learn that you are invited to attend a Chinese friend’s wedding and don’t know how to prepare, so I’m writing to give you some advice.
First of all, according to Chinese wedding custom, you ought to prepare hongbao, a red envelope containing some money. Secondly, keep in mind that you had better arrive on time or some time earlier. Additionally, you might bring a proper gift, like a cup or crystal items, which can convey your blessing. What’s more, being well-dressed will show your respect for others.
All in all, I hope these advice will be of great help to you and you will have a good time at the wedding.
优点：from which I learn that …， from which引导非限，that引导宾从；containing some money是现在分词短语作后置定语；keep in mind that…that引导宾从；which can convey your blessing， which引导非限；being well-dressed will show your respect for others.其中，being well-dressed为动名词短语做主语。
How is everything going? I ’m more than delighted to receive your letter/email. Knowing/Learning that you have difficulty in doing sth, I’m writing to give you some suggestions/tips （on how to do sth）
First of all/To begin with, you are supposed to do sth so that you can ……. What’s more, it’s important for you to do sth. In this way, ……. Last but not least, doing sth is of great benefit to sth. /has a positive/good impact on sth.（也可用句式It’s a wise idea to do sth）. That is because….
I hope you will find these suggestions useful and become better (make progress/succeed). Looking forward to your reply! Best wishes!