The Serie A leaders were beaten 2-1 by Vincenzo Montella's side last month, leaving Allegri's side needing victory by two clear goals to progress to the final.
However, Allegri does not want his side to go all-out and leave themselves at risk of a counter-attack, instead calling for a calm performance.
"We have to go to Florence to try to overturn the negative result from the first leg," said Allegri. "It won't be easy. At the moment, they're the favourites, as they have the [first leg] result in their favour.
"They're going through a good spell, playing good football and getting excellent results, so we'll have to play an intelligent game.
"We know that we're facing a team with great technique, which plays well, but we also know that we don't have to immediately win the game in the first half hour.
"It will be a long game, so a good performance and calm heads are required.
"It's not easy to win in Florence. For them, as for us, it's an important game, because it [the final] would be an important goal to achieve.
"We know we have the ability to get two goals, but we could even get them 10 minutes from the end, so we don't have to get worked up and anxious to immediately overturn the result, because that will absolutely not be simple.
"We must be very patient and make the most of the opportunities that we will have."
Juve are looking to make their first Coppa Italia final since 2012 in their hunt to win the competition for the first time in 20 years.
