Did puppy class and beginner obedience but she still jumps and nips strangers at 6 months

My Staffy puppy is 6 months old now and done teething but she still jumps on and nips strangers clothing even though I completed puppy class and beginner obedience. In the class she would jump and nip others in the first class or two but it stopped quickly and she did great passing both classes. Since 9 weeks of age when I got her from the breeder I noticed she always goes into hyper mode tail wagging a mile a second being so happy to meet and greet strangers pulling like a locomotive to get to people. She does not jump or nip me at all just strangers that meet her and other family members.

What is the quickest way to nip this behavior in the bud? I have told family members and strangers to turn away and fold their hands showing absolutely zero attention to her but that does not seem to work. When they avoid any eye or physical contact she gets even more hyper jumping up and nipping harder and more frequent. The trainer suggested keeping the gentle lead I use on her at all times when she is supervised so I have complete control of her around people.

Any suggestions or advice from others that have/had this same problem? I try to practice not jumping and nipping by taking her around family members but they all have become afraid of the nipping. So after the first nip or jump make they make noise and leave the room.

The last sentence speaks volumes to me. It's still seen as a game to your girl. Your doing the right thing advising everyone to keep hands away etc but add in an All 4 Paws on the Floor rule with a really high value treat. Everyone has to follow this rule with no exception so that there can be no confused messages.

If people are nervous your girl will pick up on this so ask them to remain calm, feel in charge & do the All 4 Paws rule. Confidence is part of the trick here.

As above be firm but fair and consistent and patient

People are going to think i work for them for the amount of times i suggest this tool.

Head Halti while out walking, complete control of the head, to stop jumping and control of the mouth to stop nipping, as for in the house, keeping a simple leash next to the front door when you let in guests, to keep her leashed to your waist until she has calmed down, distraction you could ask your guest and family to drop food as they walk by to keep her from jumping and turn their backs when she does jump.

I dislike the halti but this is one time I might agree with it for a short time while training, as it could create an unpleasant association between jumping and the resulting sensation.

We've had a problem with this with Millie as she's very sweet and so many people have done the 'oh I don't mind, here have a treat and a fuss' thing, which of course encourages it. What's worked more than anything with her is getting people to walk into her when she jumps up. Again, that makes it less nice and she gets the opposite of what she's after - instead of getting closer she gets pushed away. It more effective to take a step and push with your body rather than your hands, as hands can become a great game.

Then, as Ian says, 4 feet on the floor gets a reward. Really look out for any moment that she almost goes to jump but then changes her mind and reward her big time for that, that what she needs to keep looking to do.