One of the strongest and most effective way to educate your child

Learn to define the three main limits:

first, the things that can be done freely.
Second, the things that should never be done,
and third, the things that can be negotiated.

Never say "No" again that fast. Learn to talk with your child based on the limits mentioned above and help them aide by them. This will surely work. It's worked for me and my family.