nation in history, and so there was protection and immense advantages to be gained.

I have to agree with the above post that the prime method of control was economic, as I think it has to be in any successful colonial endeavor. I would like to add though a social idea that also contributed to Britain's ability to maintain control over the American colonies.

The colonists were British and considered themselves British. This is an important idea. They weren't American, because America didn't really exist. But they did need to distinguish themselves from the other settlers and the Native Americans. They were not Dutch or French: they were British! This holds strong during a time when England is one of, if not the most powerful nation in the world. One wants to be associated with this power and superiority. Also colonists wanted the rights of all British citizens. They did not want to separate themselves from those rights and privileges. Lastly they expected the protection of the British military, a right of the British alone, that was shared by the colonists. It was important to be British and not give up their rights and protections under the crown.

The primary control Britain used over the colonies was Economic control under Britain's economic policy of Mercantilism. Certain goods could only be shipped to Britain under the Navigation Acts, or could only be shipped on British ships. Others bound for other ports had to dock first in Britain. For the same reason, the colonies were not allowed to engage in large scale manufacturing (they were to be a source of markets for Britain and also a source of raw materials) nor coin their own money.

Otherwise, the colonies were granted a substantial degree of self government. They were able to elect their own Colonial legislatures, and although the Governor was appointed by the Crown and had veto power over any legislative decisions, the legislatures paid the governor's salary, which gave them some control over them. Soldiers were not quartered in the colonies until wartime, nor was any attempt made to tax them until Britain encountered the substantial expenses of the Seven Years War.

I would argue that economic interdependence was also part of the situation.  Although the American colonies had access to what seemed like unlimited resources, there were certain things the colonies were only able to get by importing from the motherland.  This, plus the "nationalism" mentioned in the above post and a healthy dose of fear is probably why there were dissentions between Loyalists and Rebels within the colonies.  No one liked the unfair taxation and the ever-increasingly rigid rules/laws that were passed without representation of colony leaders.  However, many were uncomfortable with being cut off from England and having to be completely self-sufficient.  It is safe to assume that they enjoyed identifying themselves as "English" and not "American" as there was a sense of superiority associated with being English. 

I would say that the British government maintained authority over the colonies in all the ways that governments everywhere do.  They may have used force a bit more than governments typically do now, but they did not maintain authority mainly through force.

Instead, I would argue that they were able to maintain authority because they got the people to consent to be ruled.  I think this is what you are talking about when you say "nationalism."  They encouraged people, for example, to identify with the King and the monarchy.  By emphasizing the people's connection to Britain in that way, they helped to ensure that people would respect British authority.