Taking a sound sleep for the child is very important, because this is the only time when the child relaxes his body and mind. Setting a proper time to sleep and to wake up is also very important, those children who sleep on time are found to be more refreshed and aware whereas those who sleep lately and spend their time in watching television or playing games late nights are found to be deprived of sleep and rest. But the most important part is to look at; with what kind of thoughts your child is going to sleep, in what state of mind he/she is sleeping? This is a crucial point that we parents usually ignore. It is vital to give happy, positive and good thoughts to your child when he is going to sleep probably a good moral bedtime story or a soothing lullaby would do it. Never argue, fight, scold or narrate a horrifying story to your child when he/she is about to sleep. Such negative activities would agitate his mind and would not let his mind to rest during sleep also. It is necessary for your child or for that matter for anyone to think good and positive before sleeping; asking your child to pray for a while or ask him/her to accompany you while you pray, would be a wonderful habit to inculcate in your child.
I disagree with you here: Arguing, fighting and scolding is something that should not be ever done in front of the child especially while the child is small. This has a very negative impact on the child's psyche. It creates fear, frustration and sadness in the child. As parents, it is their responsibility that the child should always be surrounded by positivity. The child should be made to listen to good music; made to read good books; watch good movies and spend time in outdoor activities. All these activities done throughout the day will be able to give him a good sleep as well.