To keep skunks out of the yard, don't leave garbage out overnight, and put lids on all garbage cans. Do not leave pet food out at night as they are attracted to any food sources.
It also helps to reduce the temptation of a skunk creating a den in the yard. Skunks often den underneath elevated sheds, on wood and rock piles, in crawl spaces or underneath porches and concrete slabs. Be wary of these areas, being sure to investigate them regularly. Be careful not to overwater lawns, as this causes grubs to come to the surface of the wet soil, which attracts skunks. Add extra outdoor lights as skunks don't like to be near lights.