"Proper discipline" is called "
Positive Discipline"
If you Google it, you'll find plenty of websites, books and studies for it.
Wikipedia has several studies that show 'significant' results.
Here's a webpage that has a guide for each age bracket:
The most important things seems to be-
- No spanking
- No timeouts
- No yelling/raised voices
- No grounding
- No confiscation of privileges/toys
For example, if your 10 year old didn't get his homework done because he played video games instead, don't say "The next time you don't do your homework, I'm taking away your video games". That's harmful, and causes your child to lose respect for you. Instead, say: "You seemed stressed this morning when you didn't get your homework done. Let's figure out a way together on how to get your homework done next time"
According to the professionals, if you are "kind and firm" and don't punish your children you will never have to because they will respect you and learn self discipline by your examples.