There isn’t much you can do to lower your exposure to RF radiation from smart meters. Because the low levels of energy from RF radiation have not been clearly shown to cause problems even at close range, it isn’t clear that lowering exposure to RF radiation has health benefits.
It may be possible, however, to lower exposure to cell phones and other sources of RF radiation. See the American Cancer Society’s website’s FAQ pages for visit Microwaves, Radio Waves, and Other Types of Radiofrequency Radiation, and Cellular Phones.