Visiting Beijing for the first time since October last year, Rogge praised the 2008 host nation's "magnificent" work towards staging a technically top quality Olympics.
"However, we should all remember that the Games are not judged solely by the technical proficiency of the project, but also through the perception that the world has of the Games," Rogge said in a speech.
"We must therefore ensure that while all the technical elements are in place that we do not forget to look after the less tangible elements that will ultimately shape the world's image of China and the Beijing Games."
Although Rogge did not elaborate on his concerns about the world's perception of China, Beijing's image has been tarnished since his last visit by reports of a crackdown on media freedom and concerns over human rights ahead of the Games.
"Despite the great progress that BOCOG has so far been able to achieve, my experience throughout my Olympic career has been that it is extremely important not to 'take your eye off the ball', because it is often in the moments when you lose your focus that mistakes can creep in," Rogge added.
The IOC chief toured the main Olympic Stadium in Beijing, known as the 'Bird's Nest' because of its structure of twisted steel beams, and the state-of-the-art venue for aquatic sports known as the 'Water Cube'.
Big Brother minds manners
Meanwhile, thousands of extra video cameras are being installed on Beijing's buses in an effort to improve public politeness ahead of the 2008 Olympics, Xinhua news agency said on Tuesday.
According to the state press, the camera campaign is aimed at raising the standards of courtesy in China's capital, such as giving up bus seats to the elderly, children, pregnant women and the handicapped.
Passengers caught on video giving up their seats will be recognised as 'star passengers', while cameras will also be on the lookout for bad behavior.
"As China develops, some young people have become more self-centered and simply ignore people who need seats when they get on a bus, or subway train," Xinhua said.
"With the 2008 Olympic Games only two years away, concerns about behavior are frequently raised - rude behavior such as spitting, queue-jumping and littering have made headlines recently."
Beijing Public Transport Holdings operates more than 24,000 buses in Beijing, with about 4,000 already carrying video cameras and another 3,000 expected by the end of the year.
A series of campaigns to improve people's manners and behavior, both specifically for Beijing and nationally, have been launched by Chinese authorities over the past few years.
There were no details of any awards for the 'star passengers' or penalties for those who were rude.