At an early stage, teach your child how to politely ask for things—that saying “please” is more effective than whining or crying. Praise him when he does this well—“Thank you for asking so nicely.”
Firm statements or commands like “Stop whining” are usually ineffective. Try saying, “Sweetie, just ask—you know I don’t like it when you whine.” The old standby phrase “Use your words” comes in handy here.
Teach your child to be self-sufficient: “If you want something, go and get it yourself if you can.”
Don’t respond in a frustrated or angry tone—this is simply the adult version of the behavior you’re trying to fix.