Review their bedtime routine. Do they go to bed every night at the same time, give or take 10 minutes? Children thrive on routine, and this can be your first step. The transition between play and sleep is important. Telling your children to pick up their toys, to get into bed and then turning the lights out will not work for most children, especially if they share a room. You need another activity, such as their nightly bathroom routine, sandwiched between play and bedtime.
Have your children pick up their toys and then complete their bathroom routine. This may be a nightly bath or simply brushing their teeth and washing their faces. If you typically bathe your children in the morning, you might consider moving bath time to the evening. Baths have a calming effect on children, and thus are helpful in putting them in the bedtime frame of mind. Then once they are in bed, read them a short story so they don’t begin to talk to one another. Once the story is over, it’s lights out and there is no more talking.
For naptime problems, you might have them nap in separate rooms, if that is possible, until they are able to nap in the same room without talking and playing.