Observe if any native birds or other native animals are using your exotic plants for food, nesting, or loafing. If so, it may be wise to leave them. Replacing them with natives is likely to be time-consuming and possibly unsuccessful. Determine the basic physical features of your property, such as its size, orientation, light conditions, soil, and slope. For 25 years, I have lived in a small, hilly inner-city East Austin neighborhood that is blessed with many large cedar elms and a generous sprinkling of both post oaks and live oaks.
Hackberries thrive behind old garages and along property lines, and people have planted pecans.
The soil is a sticky black clay. The ecological setting is mostly a dry, shady deciduous woodland whose native understory trees and ground cover plants have been almost entirely replaced with lawn grasses and exotic shrubs. My backyard is private, because it joins four other lots in a dense tangle of untrimmed trees and bamboo. It cannot be seen at all from the street. I did put out a birdbath, simply a large clay saucer kept full of clean water, and I maintained one or two hanging bird feeders.