I have lately had to write a number of emails in Chinese. Sometimes I am writing to people on the Mainland, sometimes to Taiwan. Sometimes I am writing old friends, but usually I am writing to scholars and professionals to introduce myself. I am old; when I started learning Chinese, not many people used email. So I have no idea about email format and etiquette in different situations. And sometimes when younger people write me emails in English, I think they are being rude without meaning to.
I think in the Mainland, you start off with 你好！ and end with some nice salutation (週末快樂!) and then 此致. I don’t know if this is the etiquette in Taiwan or not. For example, it seems to me that on the mainland, they use more exclamation marks. I think when writing to a professor I would say 您好 , rather than 你好！ or 您好！
I don’t know whether to address people as 尊敬的。
At the end, for friends it is easy enough to say something like 麻煩你了！ 多謝！ (although again, I wonder about the exclamation points). But for more formal situations, I know that letters have some extremely formal, stylized ways to sign off. Occasionally I can find a list. I just don’t really know how to use them and when to use them in an email. Like 此致…安康 or 此致…教安。
I would really appreciate some guidance. Thanks very much for your help! (Another phrase it would be helpful to know in Chinese – would you say 非常感謝您的幫助 ?)