The essential 4 steps required to sell a home

Communication
between potential buyers or their agent and the person looking after the sale (listing agent or owner). Also prompt return of all phone calls.

Reasonable asking price
Home should be priced at only slightly above its fair market value as determined by a CMA (Comparative Market Analysis)

Exposure
It's a numbers game. The more people know about a home for sale the more of a chance it will fit someone's requirements.

Accessibility
The home must be available for viewing with reasonable notice. Can't sell it if you can't show it.

This is a no-bull approach.
Some other things might make it easier to sell a home, but make no mistake of this: Unless there is communication, reasonable asking price, exposure and easy access to the property, the home simply won't sell. Period.

There are no 21 or 121 marketing points from the biggest office in the world that will sell the home unless all of the above 4 requirements are satisfied.