Simply stated (though not so easily done) -- give your home a thorough,
top-to-bottom, cleaning. Vacuum the carpets and floors, wipe clean the
cupboards and bookshelves. Make sure you get into all those hard-to-reach places: under the sofa
cushions, the spaces between the
floorboards. Move aside furniture and kitchen appliances to get behind and
underneath. Bottom line: if that proverbial cookie crumb could be hiding there, go
after it!
As each area of the home gets cleaned, make sure that everyone knows that
it's "kosher for Passover" and absolutely off-limits for any food to be brought
in there. Practical advice: start with the bedrooms, then proceed with the
living room and other common rooms, leaving the dining room and kitchen for
last, so that you can use these spaces for eating chametz as close as possible
to the "deadline."
Other places that need to be cleaned: office, car, pocketbook -- any space
that is yours by ownership, lease, or right of use.
Places you don't have to clean: a) Rooms and areas where you're absolutely
certain that no food was ever brought. b) Rooms and areas that will be
sold (see step 5).