Lewis Carroll
Eight or Nine Wise Words About Letter-Writing
The best subject, to begin with, is your friend's last letter. Write with the letter open before you. Answer his questions, and make any remarks his letter suggests. Then go on to what you want to say yourself. This arrangement is more courteous, and pleasanter for the reader, than to fill the letter with your own invaluable remarks, and then hastily answer your friend's questions in a postscript. Your friend is much more likely to enjoy your wit, after his own anxiety for information has been satisfied.