What were 2 major events that led to increased tensions between great britain and the colonies?

First of all, (just to clear this up) the conflict and tension between GB and the colonies was a lot more complex than 2 events.  The ones I will name here are important, but take them more as a symbol of the breaking ties of GB and the colonies than the only 2 things that led to the American Revolution (aka take this answer with a grain of salt, it is too simple to be complete).
1)  The Sugar Acts/Stamp Acts/Townsend Acts (1763-66):  Following the French and Indian war (also known as the 7 years war)  Britain had huge amounts of debt from fighting overseas.  Many British were outraged that they had to pay the tax alone, because they believed the colonists were responsible for the war.  So the British government did what it thought was right and taxed the colonists through 3 direct taxes.  These taxes (named above) taxed sugar, paper goods, tea, paper, paint, some metals, and a variety of other things.  Colonists were outraged that they were being directly taxed without representation in the British Government and rebelled by boycotting goods, and harming tax collectors, but one especially good example was the Boston tea party, in which Colonists dumped entire cases of British tea into the Boston Harbor to rebel against taxes.
2) Intolerable acts:  As a result of the Boston Tea Party, Britain created a series of laws aimed at punishing the colonies for their rebellious behaviour.  These were known as the Intolerable acts by colonists and included such things as closing down the Boston Harbor and requiring that the dumped tea be paid for.  This was the last straw for many radical colonists, as they believed that their basic rights had been clearly infringed.  These radicals used ideas from the Enlightenment to justify trying to sever ties with Great Britain.