Bayern finished the first half of the campaign 11 points clear at the top of the table after an unbeaten run of 17 games since the start of the season.
However, sporting director Sammer says they are keen to keep on improving.
"The players know they can keep developing," he told the club's official website. "The players [are] open to change and willing to keep on working at the details, making all our opponents feel we're a step ahead of them mentally.
"We should approach the second half of the season modestly, with respect and sensitivity. The crucial games are still to come, especially in the Champions League. So we need to stay alert.
"We want to win the league as quickly as possible. But we must be smart, professional and serious.
"We dropped off a few per cent in this respect last year and lost our rhythm. If that happens, you don't get it back overnight, we need to learn from the experience."
Sammer expects defenders Holger Badstuber and David Alaba to return in January after time on the sidelines, but captain Philipp Lahm will be out for a little longer as he recovers from an ankle problem.
He added: "Holger Badstuber has made a lot of progress, and I think he'll resume team training in early January.
"David Alaba might need a few more days, but he'll be back in the thick of it in the course of the training camp.
"The timeline with regards to Philipp Lahm is that he could be back by mid to late-February.
"As for Javi Martinez and Thiago [Alcantara], I'm not going to offer an opinion. We'll give them all the time in the world, because all that matters is getting them fit again."
