Campbell puts his England longevity down to surrounding himself with good people and he advises the Gateshead-born striker to do the same.
He said: "He's come on leaps and bounds. Everyone knows he has the raw talent.
"People at the club have to make sure they nurture that and channel it in the right areas.
"And he has to say, 'What do I want out of my career?' He works hard but there are a few things he's going to have to work at over the next two or three years.
"That will determine how long he has in his England career. It's not about how you get into the England team, it's if you can stay there.
"You have to be humble and respect where you are in football. You have to be willing to listen and learn and train hard.
"You have to be like a sponge and take in all the information - the right information."