Basically, before the war there was salutory neglect.
Then when King George III became the King of England, he enforced merchantilism and passed the Navigation Acts.
Then came things like the Proclamation of 1763. Sugar and Quartering Acts.
England passed the Stamp Act of 1765, and the colonists boycotted British goods until Britian was forced to repeal it.
That same day, England passed the Declaratory Act.
The colonists were getting angry with the new taxes and rebellions like the Sons of Liberty started to appear.
Other things happened, like the Boston Massacre followed by the Boston Tea Party which resulted n England closing the port of Boston and passing what the colonists called the "Intolerable Acts."
The taxes weren't exactly what bothered the colonists, but they had no representation in Parliament so they felt it was unfair to be taxed without say.
Not long after there were the battles of Lexington and Concord, officially starting the war.
If you need other info, find a website that has the Declaration of Independence on it. Thomas Jefferson wrote it and sent it to King George III telling him all about every wrong England had done.