Berahino suffered a series of injuries last season but has battled back strongly and is set to be given a new contract after a series of impressive performances so far this term.
McAuley says the deal is a reward for Berahino's hard work but insists he must keep the same attitude and not become distracted, amid talk of a senior England call-up and even reported interest from big-spending Monaco.
"He's worked really hard so it's nice for him," McAuley said in the Birmingham Mail. "It's up to us to keep him working hard and keep him progressing. We need to take his potential and turn him into a top-class potential.
"We keep telling him to keep shooting. He's getting himself in situations and maybe last season he wasn't shooting. He would have tried to look for a pass. He's getting his shots off and getting his rewards for it.
"He had the injury last season, got his head right during that. Through the summer he's worked really hard and in pre-season he was flying. He's getting his rewards.
"He realises that the hard work he's done has moved him a level into the first team and he's hungry to stay there. That's nice to see from a young player.
"He's kept his head down and let his football do the talking. That's important. It shows a level head and a maturity in such a young player."
McAuley thinks it is important not to expect too much from Berahino as he continues his development.
He said: "He's a good lad but we don't want to build him up too much and put a lot of pressure on his shoulders.
"He's doing that himself with his performances and getting headlines and goals. That's important.
"That gives him the belief and confidence that he can do it in the Premier League and he's showing that."