This was discussed[0] at great length nearly 950 days ago. A great comment from PG[1] was:

    Be brief and say what you want.

As I say, the discussion is long, although subsequent submissions of the same item[2][3] got no love at all.

A related item is "How to Get Busy People to Take Action When You Send an Email." That's also been submitted several times[4][5][6], but not got any discussion at all.

[0] https://news.ycombinator.com/item?id=2532955

[1] https://news.ycombinator.com/item?id=2533379

[2] https://news.ycombinator.com/item?id=4621604

[3] https://news.ycombinator.com/item?id=4589543

[4] https://news.ycombinator.com/item?id=6832732

[5] https://news.ycombinator.com/item?id=6451658

[6] https://news.ycombinator.com/item?id=6274627