The 2011-12 English champions lost their crown to local rivals Manchester United last week.
The Argentinian full-back told Sky Sports News: "We are working well and we know how difficult it is to win the title. The Premiership in one of the most competitive leagues in the world.
"But we have probably been a bit inconsistent this year, not like last season and probably that has cost us the title, but we are working to improve, keep winning trophies and we have the [FA] Cup final at Wembley.
"It is always special to win that competition as well so we'll try to come back stronger next year and try to win the title back."
City will face Wigan Athletic in the FA Cup final next month.