From 1750 to 1776, there was increasing tension between England and the colonists. Parliament passed many laws to increase taxes within the colonies. This obviously didn't settle well with the colonists. They wanted to do their own thing and have their own identity without the English controlling every part of their lives. In response to these laws, the colonies united and formed the identity of Americans as the United States of America.
In 1754, the Pennsylvania Gazette printed a cartoon of a snake divided into eight pieces with the words "Join, or Die." underneath it (A). The pieces of the snake represented the colonies - New England was represented as one piece. This cartoon was showing the colonists the importance of unity. If you ask me that's quite harsh, "Join or Die" doesn't exactly give you very many options. Later that year, Benjamin Franklin introduced the Albany Plan of Union, which attempted to unite all of the colonies.
Though, the plan was not carried out because several colonists and the English Parliament refused to agree with the idea. Even still, this was a major first step towards colony unity.
The French and Indian War, also known as the Seven Years' War, lasted from 1756 to 1763. Because of the war, England had accumulated a huge debt. They began to tax the colonies in order to pay off the expenses. Parliament passed the Sugar Act in 1764, the Stamp Act in 1765, the Townshend Acts in 1767, the Tea Act in 1773, and finally the Intolerable Acts in 1774. Obviously the colonists weren't just going to let this go, so they protested "No Taxation without Representation." The colonists also formed the Stamp Act Congress in response to the Stamp Act and they wrote and sent a "Declaration of...