IN YOUR HOME:
Floor/carpet treatments such as diatomaceous earth (the fossilized shells of one-celled organisms called diatoms) and boric acid–derived powders will kill flea larvae, primarily through dessication (drying). Exterminators use borates; you can either hire professionals to treat your home or do it yourself. For a serious flea problem, it may be worth paying a professional since their work is guaranteed.
Vacuuming is very effective against flea eggs and might even catch a few adults. To keep the eggs from hatching or the fleas from escaping, discard the bag immediately or use an herbal flea spray in the vacuum bag or container, either before or right after you vacuum.
IN THE YARD:
Beneficial nematodes eat flea eggs and will help control flea populations outdoors.
Garden-grade diatomaceous earth is very effective outdoors as well. Concentrate on areas under shrubs and decks and other cool shady spots where animals (such as rodents, raccoons, and outdoor and feral cats) have access.
It takes patience, diligence, and persistence, but you can win the war against fleas!