Many causes of the American Revolution can be identified. The greatest single cause can be considered financial. While the cultural myth of the Revolution champions philosophy and enlightenment as the main motives, we find that these justifications were developed as propaganda to motivate the colonists into war. The famous slogan, "No taxation without representation" is based in truth, but in reality was a questionable demand.
The cause for the taxation, and anxiety over it, sheds some light onto the actual decision makers reasonings. England had recently spent great deals of money defending the colonists from Native Americans and the French in the French and Indian War. The origins for the war included colonists expanding into territories they had no right to be in in the first place, provoking the Native American attacks.
The debt accumulated from the war, prompted the increased tax on everyday products, like tea. It is interesting to note that, thanks to the successfulness of propaganda, colonists refused to buy English tea to the point that the price of the tea was reduced so that even with the tax it would have been the cheapest drink to purchase, cheaper than coffee or teas from other countries.
The question of representation is more suspect due to the physical limitations of the time. Due to the expense, time, and distance of travel, meaningful representation for the colonists was all but impossible. Of course they did have representatives who spoke on their behalf, informing Parliament of the colonies general wishes including westward expansion, they had no way to cast votes.
In the eyes of Parliament, the lengthy process of getting word to the colonies, collecting their votes, and getting them to England was simply too time consuming and would have backed up legislation.
Another of the causes of the American Revolution then, as in all wars, is propaganda. Thomas Paine's "Common Sense" is such an example. Now a classic of American philosophy, at the time it was a pamphlet written to incite the largely indifferent public to go to war. The average colonist payed little attention to, nor cared about politics, representation, or who was passing the laws. Considering after the revolution, the voting population was constricted to wealthy, land owning, white men, we can compare to before the revolution where political participation was the same.
Events like the Boston Tea Party (carried out by a relatively small group of people) and Boston Massacre became canonized as great American Events. The Boston Massacre reveals the propaganda at play. You may know it as the accursed firing of unarmed peaceful protestors by unprovoked English soldiers, but that is propaganda.
The truth of the matter was the soldiers in question where in Boston to protect against riots that had already been happening in response to the Townshend Act. The unpopular troops where at their post, being insulted by a crowd, and having things such as rocks hidden in snow thrown at them. So the one sidedness of the event is less clear than the story as told to the colonists after the fact.
Money, tied up in the desire for westward expansion, was the prime motivator for revolution amongst the elite, who then crafted philosophical propaganda to create popular support. Justifications were created and distributed, giving us "No taxation without representation." Of course there are numerous other factors at play at the time, but these two elements were the main keys.