Barkley, who joined last summer from Luton for £5million, scored four goals in 29 appearances in all competitions, making several important contributions off the bench.
But the 31-year-old was limited to only six outings, all of them as substitute, from January onwards as calf and knee issues kept him sidelined for more than three months.
Emery believes the former Everton and Chelsea star still has a big role to play moving forward.
The Villa boss said: “For next season, I want the best of him. I believe in him. I believe in his performances and how he can help us—like he was doing.
“He scored three, four, five goals this season. He contributed a lot and was adapting to us, improving progressively.
“Our demands—tactically and defensively—are very high.
“Last year, we needed to correct a few things with him individually. But I am very happy with him.
“Hopefully, he can maintain consistency through the summer, even while resting, so he can be ready for next year.”
Barkley, who previously spent the 2020-21 season on loan at Villa during Dean Smith’s time as head coach, returned last summer having revived his career during an impressive season at Luton Town.
The England international had joined the Hatters from Nice, after leaving Chelsea a year earlier on a free transfer following a largely frustrating four seasons with the London club.
He made only three Premier League starts for Villa this season but scored his fourth goal of the campaign in January’s 2-1 win over Leicester, a week before being forced off with injury in an FA Cup third round tie with West Ham.
Barkley also scored a late winner in Villa’s 3-2 Champions League win at RB Leipzig last December, a result which helped Emery’s team finish in the top eight of the group phase.
“Last year, we analysed him at Luton, and he had a fantastic season,” said Emery.
“Fantastic consistency—scoring goals, performing very well—maybe playing his best football in a long time.
“He’s played for a long time: at Everton, at Chelsea. But he is still young at 31 years old.
“It was necessary for him to adapt to our demands this year. When he was at his best, he got injured. And he was out for three months.
“Of course, that's a long time. But now he is feeling good again.”