I read somewhere, might have been A People's History of the United States, that Native American tribes and civilizations were much more advanced than they are often given credit in western history books, though I can't remember the details. What were things really like?
Contrary to popular belief, the America's were densely populated, and not quite the "virgin land" that commercials like The Crying Indian would have us believe. This was referred to by Charles C. Mann in his book 1491 as "the pristine myth," which he defines as "the belief that the Americas in 1491 were an almost untouched, even Edenic land, 'untrammeled by man.'" Mann reversely argues that "an 800- or 1000-mile swath of western Amazonia was occupied by a previously unknown mix of cultures that radically reshaped the landscape around them."
This means that Natives were consciously modifying their environment to fulfill their needs, which directly contradicts the narrative of the 16th century that the Natives were child-like and helpless. Unfortunately, most American History textbooks leave this out, which further perpetuates the 'the pristine myth.'
Sources: Crying Indian Commercial - https://www.youtube.com/watch?v=j7OHG7tHrNM
1491 by Charles C. Mann
North America is a place of enormous diversity, stretching from the tropical marshes of Darién to the arctic tundra of the North Slope. It would certainly be helpful to narrow down the focus of your question in order to attract more detailed answers. There's also considerable ambiguity in phrases like "more advanced than they are often given credit." What does 'advanced' mean in this context, and what credit do you feel is generally given to Americas' indigenous cultures?
One thing I will mention to help get you started, since /u/Zappp_Branigan already brought it up, is the idea of landscape manipulation. While it's true that indigenous cultures have been altering the landscape of the Americas for millennia, it should not be assumed that this necessarily takes the same form as European styles of landscape management. The difference in strategies is part of the reason the Pristine Myth developed in the first place. Europeans manage their land to maximize the yields of fields and pastures. Meanwhile in the Eastern Woodlands (roughly the US east of the Mississippi, with some spillover to the west and into Canada) the manipulation of forest succession was of vital importance. After a few years, farmland was returned to the forest, providing habitat for animals that the people of the region relied on as much as Europeans relied on the livestock in their pastures, as well as creating space for a variety of wild and pseudo-domesticated plants that were also important sources of food, medicine, and raw materials. When Europeans arrived, they saw a mix of extensive farmland and vast forests. To them, those forests needed taming to become productive farmland and pastures. They didn't see them for what they really were--gardens that needed tending.
In addition to the previously mentioned 1491, I'd recommend William Cronon's Changes in the Land: Indians, Colonists, and the Ecology of New England as a good introduction to the concept. It was written in 1983 and was influential in busting the Pristine Myth; however, due to its age, it has its own problems you should be aware of--most problematically, Cronon tends to minimize the intentional aspects of indigenous landscape management practices. He tends to paint it more as a happy accident, rather than something people were doing deliberately with awareness of the consequences of their actions.