How do I train my 7 month old lab to ignore strangers?

well obedience cl will help. but please keep in mind she is still a baby at 7 months and still learning. the other thing she is a lab. My 4 yr old girl (lab) has been thru cles and training and she still every once in awhile gets over excited when other people are around and tries not to listen to me. she would never do this if we were alone. It is the Lab in them.