First: An authoritative parent has clear expectations and consequences and is affectionate toward his or her child. The authoritative parent allows for flexibility and collaborative problem solving with the child when dealing with behavioral challenges. This is the most effective form of parenting.
Second: An authoritarian parent has clear expectations and consequences, but shows little affection toward his or her child. The parent may say things like, "because I'm the Mommy, that's why." This is a less effective form of parenting.
Third: A permissive parent shows lots of affection toward his or her child but provides little discipline. This is a less effective form of parenting.
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What is discipline?
Discipline is the process teaching a child what is okay and what is not okay. This is when we teach the children the rules and evolving methods for them to adapt it.

How do we maintain discipline? 
1. Be respectful to the child: Again and again and again! If you show respect to the child since an early age, your child will most likely be respectful to you, to his friends and family, to his things...and to people in his/her life as they grow up. Remember that it is OKAY to apologize if you overreact, or if you "lose it" with your child. 
2. Communicate with your child: Children should not be surprised with new plans/ideas/techniques/rules...etc. Communicate why a certain rule is there, and do not underestimate the child's ability to understand. What we tell our children becomes the voice inside their head later on.
3. Be consistent: A rule is a rule, even in public. If we make an exception once, then it is not a rule anymore. However, we can always talk about adjustments in certain situations and agree together on something. But if we cater for the child's request in public just because he/she threw a tantrum, trust me the tantrums will continue probably forever but with different levels.
4. Go down to their level: Imagine a person double or triple your size talking to you (or probably shouting at you), and you're looking up to this HUGE and TALL person. It sounds scary right? When talking to/addressing a child, sit on your knees, or sit beside them. It makes the child feel more safe, and can relate more to what you're saying. Do not expect the child to go up to your level, you should rather go down to theirs. 
4. Move on:  You both agree on something, and the child abides by the rules and goes through the consequences, when it's done: DON'T GO BACK TO IT! Don't continue to lecture the child on what he/she did wrong, and don't keep on asking for more apologies. When it's done, it's done!

Always remember this: what we do to/with our children, becomes a reflection of their personalities in the future. And what we say to them, becomes the voices inside their heads.