My children are very young, I have little experience in this field but I have a request for a children's etiquette text.
I can tell you that my oldest child, my two year old, says "please", "thank you," and "thanks." But more importantly, she says, "I love you too, Mama." And that's what really matters to me right now. We did not drill her on these first manners of hers, we all just try to respect one another and she acts in turn.
Down the road, I may need more help and by request I can tell you that I will consider these resources for manners; my first choice is not a book but rather the firm way on down south called Southern Protocol, which I wrote on previously. Secondly, the etiquette interactive seminars I mentioned previously, such as occur at the Don Cesar during family vaca's. Just a guess, but it is probably a lot more interesting to the child to be involved in activity-based learning with others their age...
Failing that, I could and in some cases, have, read the texts mentioned here.