Parenting during the first five years is certainly the most rewarding and enjoyable experience but also physically and emotionally demanding.
This in fact is the golden period for parents (i.e. 2 to 5 years of your child) where you can form the child's character. This is because the children of this age are very innocent and know only the language of love and affection. They are just like a ball of clay; you can mould and give them the shape you like. They also have tremendous grasping power. As per the research on child psychology a child can grasp almost 50% of the knowledge of life.
Once you have a clear picture of your child's behaviour pattern, you are ready to change it by triggers and consequences. You may have to try and ignore certain behavioural pattern, try not to give in, remove certain privileges, look and sound as if you mean it when asking your child to do something. Most importantly concentrate on encouraging and rewarding good behaviour all the time!