A child is the biggest asset of any person. The success of a child primarily depends upon the way he is brought up. Parents are initial teachers of the child. Child should be reminded of his good qualities. It is not necessary that the child should be punished for his wrong doings but the correct path may be shown by explaining and persuasion. Even if you are angry at some wrong doing, cool down first and then talk to him. After all hitting or spanking the children is not the right solution of any problem.
A child will primarily learn from the parents. If you want the child to be well mannered, parents will have to set an example. Telling a child in a positive tone will be more helpful than telling in negative. Reward for good deeds will be very helpful in disciplining a child, but this should never be understood as bribery for doing something. Setting a routine and making him follow it is a good way of disciplining. Even if the child gets bored and does not follow his routine, make him rest for some time or let him do something of his choice before returning to routine. Even if you have to be harsh with him, look directly in his eyes and explain firmly. This way the child will be more receptive. At any cost avoid corporal punishment. This will make the child very timid and will stop listening to verbal commands.
Kids are fond of some things like watching cartoons or other children TV programmes. Let the child enjoy them for some time, set routine for this, like he will be able to watch for a particular length of time after completing home work. Never tell him that he will not watch such shows or do something of his liking, this way you will make him retaliate. If he is not doing the work assigned to him then as a punishment you can direct him not to do his favourite things, but the moment he does it, let him enjoy.
Try to stick to what you have said, otherwise the child will get the impression that he can get away by disobeying you. If the child has performed well in school give him some reward, may be offered ice cream or cake of his choice. Remember not to hit him even if he has not done well in studies. Explaining is best way of disciplining.
It is essential to distinguish between the way you are to handle small kids and grown up children. Grown up children often rise in rebellion easily. Remember to be friendly with them so that they do not feel lack of attention or affection at home. If something of this nature creeps up in their mind they will try to find happiness outside and may fall in bad company.
So, the key is, be calm, understand the root of problem and then try to find solution accordingly instead of hitting or spanking the child to countdown your anger and frustration.