9 month-old Lab Jumpin on people

Question
I have a female 9-month-old Lab who is the sweetest dog . She's very playful & smart. We have taught her basic commands like "sit", "stay", "lay". We have been trying to teach her not to jump on people when she greets them because i have little nieces & nephews that even though they L0VE to play with her, she is a lot bigger & could hurt them. I don't know what we are doing wrong that she is just not understanding that command. Is there any good effective way of teaching her not to greet people by jumping on them?

Answer
Consistently is very important in correcting jumping and other problems. Quickly correcting him each and every time he jumps on somebody is very important. He must never get the affection he wants. A number of things have been used. One of the most gentle is to grab his front paws and hold him up. The traditional knee to the chest or step on his paws are fading from use. As part of the the trend away from negative methods, just step backwards leaving his front feet to fall to the floor. After a few tries, the dog may just stand there looking confused.