1. Minimal government intervention. The forces of free market will guide production, exchange, and distribution.
2. Self interestedness of economic behavior. Think of the old quote by Adam smith that reads something like "its not from the benevolence of the baker or butcher that we expect our dinner, but because of their regard for their own well being"
3. Harmoney of interests. When we all act in a way that's best for us, everyone ends up better off.
4. Put the focus on specific laws. The school was developed in a newtonian era, which effected their mindset. They looked for binding phenomenon - binding laws - that always govern economic activity.
5. All activities and resources contribute to a nations wealth, not just commerce as the merchantalists believed or land and agriculture as the physiocrats believed.
Hope that helps!