I know in my house, my younger siblings fight a lot. But if at the start of the meal everybody is still in a good mood, and we start singing, it gets everybody calm — I have some very musical brothers, and as long as they start singing, they don’t stop, and we have beautiful meals. Then, when my father says a Dvar Torah, they start bickering — and the trick is to begin the Torah by asking them a question, and listen to their answer or wait until they are stumped before starting YOUR torah. That get’s them interested. It always works — and they aren’t calm to start with!!!
(My younger siblings are aged 13, 9, 7)