When can we start actual disciplining the child?

It's normally said that babies are very smart and, unlike what we think about them, they pick up things very fast. So, I'd say start from the time your baby starts to respond to your name calls. Discipline does not mean that you spank your child or punish him for not finishing his meals. Discipline means establishing a routine for your child and other such things that make your child understand the importance of time. This also establishes a sense of responsibility in your baby. http://www.parents.com/baby/development/behavioral/when-should-you-start-disciplining/