1. Have a think about when your child whines. What happened immediately before your child started whining? Or that day? Could it be that your child is tired or sick? Could it be that your child was trying to get your attention and couldn't? If you notice patterns in causation, try to put processes in place to avoid these triggers.
2. Be clear and be consistent. Tell you child that you would love to address your child's needs, but you expect him or her to ask in a nice voice. When your child whines, say "I would love to help you, but I expect you to ask in a nice voice." Get caretakers, parents, grandparents on the same page. If whining accomplishes something for your child, your child will keep on whining.
3. Model how to ask nicely. Your child may not know what "whining" is. Make sure it is clear to your child what whining is and what a nice voice or a nice way to ask is too.
4. Reinforce the positive behavior. When your child uses a nice voice, make sure to reinforce this behavior. This is the most powerful tool in changing behavior. Take the time - whenever your child uses a nice voice or asks for something without whining - to say "Good use of a nice voice!" or "Yay! I get to help you because you used a nice voice. This must make you proud of yourself that you used a nice voice and were able to accomplish what you wanted!"
5. Reflect and improve. Think about what worked and what did not work that day in teaching your child how not to whine. Did you get angry? What can you do to approach the situation in a measured way? Ideas include taking time to take deep breaths for yourself or making sure you are rested or calm when your child returns from school or you see your child at night. Take the time you need to clear your own mind so you can be a better teacher.