If experience teaches a parent anything, it is that in order for mature adults to evolve from the tantrums of a four year old at a supermarket, or the moody teenager that hates her parents, then there will be times when parents have to choose whether or not they want to raise an independent mature adult or a lifetime disrespectful mooch.
The thing is, as young parents we don't always know that the moment of the tantrum is a determining indelible memory in the subconscious. All we hear is the crying, whining, or argument, and we want to end it! It is easier to give them a warning, again, and hope they learned from our disappointed look and disapproving words that they are not to do that again.
However, parenting experts and child psychologists do agree on some very important and basic steps that must be incorporated into discipline if we are to see positive results, and hope for the emergence of that oh so elusive mature responsible adult. I have outlined some of these below.
Children learn more from what they see than what they are told to do. If you yell at your husband, they will learn to yell at their friends, if you gossip, they will do the same, if you talk with your mouth full, they will follow suit. If every time your mom comes over you complain about her, guess who is going to avoid you in later years? Children do as you do, not as you say.
Children of different ages, but specially young teens, or "tweens", are very susceptible to positive reinforcement. Make sure that everyday you mention something wonderful the child did. It can be as simple, as "I'm so happy you got up and made it on the school bus on time." or "I really like it when you help me clear the table." When situations arise that require a long lecture or discipline, they will know that you do recognize the good things they bring to each day.
Children's brains are not completely developed until about age 21. Yes! Believe it or not a 19 year old can still be struggling with responsibility because the prefrontal cortex that controls impulse is still not completely developed. This means it can be specially difficult for a 16 year old to moderate behavior by considering the future consequences of their current actions. Therefore they need to see immediate consequences to help start creating the neural pathways which will later warn them not to go through with that action. This is where parenting is crucial. Discipline needs to be immediate, firm, and consistent. If going over their cell phone minutes means they loose their cell phone for a week that month, then follow through with it immediately. If it is a preschooler who refuses to sit through his meal without getting up 3 times to look for his PSP, then the "timeout" must happen immediately. Oh, they will cry, yell, and may even tell you they hate you. This is where you must stay firm. Yes, kids will not like you many times throughout their lives, but if you parent correctly, they will love and respect you when they are adults.