Experts and BHG readers answer.
abundance of clover in the lawn
Late summer and early fall (when temps have moderated some) are good times to treat. Use a 2- or 3-way broadleaf weed killer and spray according to directions. I feel the sprays work better than the granulars.
Clover may, and creeping charley definitely will, require a second treatment 2-3 weeks after the first for complete control.