The Navigation Acts, developed throughout the seventeenth and eighteenth centuries, sought to maintain control over trade within the British Empire. Specifically, revisions made in 1760 pivoted the focus to controlling colonial economies.
First, the acts made strict rules against the use of foreign ships and required all trade ships to employ at least 75% English and colonial crews. The acts also prohibited the export of many specific products and demanded imports must be sourced through Britain.
This had the effect of ensuring that colonies were decidedly dependent on Britain. Colonies could mostly only make money by selling raw goods (as colonies were primarily agricultural) to Britain and then could only buy back finished products (at a higher cost, of course) from Britain, which was more industrialized. This limited colonial economies and ensured Britain could maintain its trade advantages.