The German had a strong season for Mercedes in 2013, winning the Monaco and British Grands Prix, but finished 18 points behind his team-mate.
Although Hamilton threatened to gain the upper-hand in the build-up to the August break, Rosberg had a strong start and finish to the year and ended up with the better result in six of the last nine races this season.
Even though he finished a career-best sixth in the championship and led more laps than any driver other than Sebastian Vettel, he still believes there is more to come.
"I'm not happy, but I am pleased with this season," Rosberg told AUTOSPORT when asked about his performance relative to Hamilton. "I had some great ups but also a few downs.
"My goal was to improve since last year, which worked out fine for me with two wins.
"But with a cleaner season next year, I want to stay in front of my team-mate on points.
"If we want to become the best, we need to be more consistent next year, but I am sure that we are able to sort this out.
"We have a really strong team now and great technical people joined us."
Rosberg has already gained experience of the 2014 car in the Mercedes simulator and will start his serious preparations for the season at the end of the week.
He is due at the team's Brackley factory on Friday for seat fitting work and engineering meetings.
"I can't wait to step in the new car and would love to drive the first race next Sunday," said Rosberg.
"It's the most exciting project since I'm in F1 and it will also be my busiest winter.
"I got a first impression of the new car when I was in the simulator recently.
"In the coming week, the next steps will follow, for example with the seat fitting."
Rosberg's 2013 season is his best in F1 by all measures - here are his stats:
Pole positions: 3
Front row starts: 7 (including poles)
Laps led: 104
Championship position: 6th