DEAR ABBY: I have my granddaughters write thank-you notes to everyone who gave them presents for Christmas, birthdays and special events. They are 7 and 8 years old now. They have fun drawing pictures and mailing the letters, and the recipients enjoy receiving their notes. I would like to order your Letters Booklet because it contains samples of many other types of correspondence. LINDA IN CENTERVILLE, TEXAS DEAR LINDA: You are giving your granddaughters an early lesson in good manners, and your idea of having them draw pictures on their thank-you notes is clever. Because most children like to draw, some parents ...