The Sri Lankans must first qualify for the tournament by playing in a four-team round robin series with the West Indies, Bangladesh and Zimbabwe, with the two highest placed teams joining the main draw in the Champions Trophy.
"We have learnt from our mistakes," Jayawardene said.
"When we came here last time, we faced initial difficulties following new rules (power play and super sub) which gave so much importance to the toss, but I think we have improved since then."
Sri Lanka coach Tom Moody, who played one-day cricket for Australia, backed up his captain's comments ahead of the qualifying series.
"We are not the same team that visited India last time. We are now a better, stronger unit," said Moody.
"A lot of young guys have come and done well in international cricket. There is a significant improvement, especially in fielding."
"The focus now is on playing qualifying matches which will help our players adjust to Indian conditions before the main tournament starts," Moody added.
The Sri Lankans defeated England 5-0 in a one-day series recently and go into the Champions Trophy buoyed by the form of their captain who scored 328 runs in those five matches in England.
Freedom leads to form
"It's nice to be in form," said Jayawardene.
Jayawardene is looking to
continue his good batting form
"I now have a regular batting slot which has given me a lot of freedom. It was a bit difficult to be consistent in the initial years (of my career) when I had no fixed batting place."
The in-form batsman also singled out experienced openers Marvan Atapattu and Sanath Jayasuriya as key players to Sri Lanka's challenge.
"Marvan's return from injury is a bonus. He is an experienced batsman and has given us more options. It is also good to see Sanath in good form. He is a great asset."
Sri Lanka open the qualifying tournament when they take on Bangladesh in Mohali on October 7, while the West Indies play Zimbabwe in Ahmedabad the following day.
Australia, India, and England await the second highest qualifier in Group A of the main tournament, while the highest qualifier will join South Africa, Pakistan, and New Zealand in Group B.
Host nation India will play England in the opening match of the Champions Trophy in Jaipur on October 15, with the final to be played in Mumbai on November 5.