I agree with 'nanny' but would also add, be consistent. Don't threaten a consequence and not see it through. Use time outs appropriately, a minute for every year (eg. 3 years, old 3 minutes) or they forget why they are being disciplined. I'm from the school of never hitting a child. It only teaches them to react with violence when they don't get their way. After they have finished their punishment, make sure you drop it there, nothing else need be said; make sure you show them you love them in spite of their behavior. Kids will respond as you do, no yelling, just calmly explain the consequence and why they are being punished. Children mimic their parents, be careful what you teach them. Every child is different, treat them as individuals.