David signed for Juve last week after coming off contract from Lille.
Tardelli said of the Canada international striker: "I hope David succeeds in Turin too. He's scored a lot in France in recent years, never scoring less than 25 goals.
"Juventus, however, isn't Lille, and it's not easy to maintain that level in Serie A. If he asked me for advice? It wouldn't require a long speech, just a few words: at Juventus you have to score goals and win."
On Dusan Vlahovic potentially being granted a free transfer, Tardelli also told La Gazzetta dello Sport: "Leaving on a free transfer isn't in anyone's best interest, neither Juventus nor Vlahovic.
"The Bianconeri wouldn't earn anything next summer. But the Serbian, by playing less or at least not enough, would risk losing his national team in the year of the World Cup. Dusan and the club need to talk and find a compromise to best end a story that started out great but then didn't live up to expectations.
"Milan or abroad? If I need to cash in, I'll even sell him to Milan. Selling is a good idea, but no freebies."