Grealish has emerged as a top prospect for Villa over the back end of the 2014/15 campaign, and Agbonlahor is enjoying watching the 19-year-old progress.
He doesn't feel that Grealish is at the top of his game yet, though, and expects the attacking midfielder to unlock even more potential in the years ahead.
"Anyone who is watching him now, they haven't seen anything yet," Agbonlahor said. "He skips past players in training every day - these are senior professionals.
"Everyone is astonished at how easy it is for him. I think there's a lot more to come from him. If you're a Villa fan, you should be excited. I give him advice considering what I have been through in the game already. But he's clever on the pitch.
"He knows the game. He understands the game. He does things that people don't expect."
Grealish has been entrusted with huge responsibility by Tim Sherwood since the ex-Tottenham Hotspur head coach inherited the reins from Paul Lambert, but he has repaid his manager's faith.
Sherwood made the Republic of Ireland youth international the creative fulcrum of his side, and Grealish has thrived in the role.
The skilful youngster has shown just how confident he is and he has added a new dimension to Villa's attack.
Grealish will now be looking to push on even further next season, where the Claret and Blues will be aiming to break into the top half of the Premier League table.