The Austria international proved to be one of the highlights of a difficult season for Villa, with the 21-year-old impressing as he scored 12 goals in 38 appearances for the club in the 2012/13 campaign.
Lambert promoted Weimann to the first team after he had largely been on the fringes under Alex McLeish and he feels the player has benefited from a regular run in the side.
"The big thing that strikes me is his work ethic. That's the big thing," Lambert told the club's official website.
"You don't need to be the greatest player on the planet but if you have got a work ethic it can take you far in the game, if you've got that drive and hunger to succeed.
"The thing is with Andi in the previous year, he was probably in and out all of the time. What we've done is given him a sustained run."
Lambert was also keen to praise Weimann's temperament and versatility after he was asked to play out of his favoured position for much of last season.
"I know his main position is probably through the middle off a striker but his performances on that right side, coming off the lines and things like that, have been outstanding," added the Scotsman.
"Andi is a natural finisher. He knows where the goal is which is great for us. He has been exceptional.
"Success won't go to his head, I don't think. I don't think money will go to his head and that is a big compliment.
"Whatever he earns or whatever success he gets, I think he'll always be the same."