1. "Deliberative assemblies shall be widely established and all matters decided by public discussion."
This in fact never really happened. A parliament with no real power was established, and the oligarchy remained in real political control. They did allow more though in the way of public assemblies and political discourse.
2. "All classes, high and low, shall unite in vigorously carrying out the administration of the affairs of state."
This declaration was important, especially in conjunction with article three. Essentially, it means that all people can be employed by the government, and that everybody should help the government as much as possible, regardless of position.
3. "The common people, no less than the civil and military officials, shall each be allowed to pursue his own calling so that there may be no discontent."
This very important statement abolished the long standing feudal order of Japan, under which all subjects occupied from birth a specific rank within the social and economic structure.
4. "Evil customs of the past shall be broken off and everything based upon the just laws of Nature."
This is a blanket declaration of reform.
5. "Knowledge shall be sought throughout the world so as to strengthen the foundation of Imperial Rule."
This might seem familiar to anyone who has read about the Taika Reforms: the difference here is that instead of borrowing from China as in the past, Japan will borrow from Western powers, mostly the U.S.