What are some grievances that led to the American Revolution?

Perhaps the biggest grievance was that the American colonists were subject to taxation, yet were denied political representation in British Parliament. Americans didn't think it was fair that taxes could be imposed upon them without their vote; taxes were a necessary evil, but if they were going to be levied, then those subjected to them should at least have a say in how they were devised and how they were to be applied.
Another grievance was the permanent stationing of British troops on American soil. The British insisted that this was necessary to protect the colonies from foreign invasion and from attacks by Native American tribes. But many Americans were suspicious; for them, standing armies were potential instruments of tyranny. Like many people back in the mother country, they thought that armies should only be raised as and when they were needed, to fight specific conflicts. They should not, however, be a permanent feature, because it would then be far too easy for the government of the day to use such standing armies for the repression of their political opponents, with disastrous consequences for liberty.
This was an especially acute concern for the American colonists, because as we saw earlier, they had no political representation at Westminster and therefore could not exercise any control or scrutiny over the British government's deployment of troops.