Native plants provide food for bees and birds, require minimal watering or fertilizer, and reduce the need to mow and rake. Even a small patch of native plants can be beneficial to the environment.
The easiest way to get started with natives is to plant live plants rather than seeds. One can prepare the site by putting down cardboard or dark plastic for a couple months to kill existing plants, though it also works to just remove or trim undesirable plants as needed. If the native plants like a spot, they will overshadow and eventually eliminate what was there before. Leaving a strip of lawn around the edge of the garden reassures the neighbors that the yard is not just neglected.
Here are some examples of native plantings in the yards of our church family.