The only person who can make sure he fulfils his potential is himself. At the moment he isn't going to do it unless he takes a look at himself and tries to improve on the areas that he has weaknesses, of which there are a few glaring ones.
When things aren't going right for him he doesn't put in the hard work to get people off his back. He ambles round looking lost and it understandably annoys the fans, and no doubt the manager too. He gives the ball away in stupid situations when there is no need, and he doesn't show the aggression that someone with his physique should. For me if he doesn't work on those parts of his game then he won't ever be the player he could be.
Having said that, despite a poor first half, I thought for most of the second half he had a good game and retained possession well. He stuck to the basics when needed and popped up with an important goal so fair play to him. I'd love to see him succeed but i'm losing patience with him now and I feel time is running out. At the moment, as a club we can't afford to lose talented players like him as the alternatives are players like Cleverley but by the end of next season, if we have started to make the progress we expect with transfers I think Barkley could be on the way out.