Quick response to buyer's questions.
Asks tons of qualifying questions. Size, Price, Pets, Schools, gated/not gated, amenities, etc.
Doesn't show buyers homes they specifically said they don't want.
Doesn't show homes ridiculously out of the buyers price range.
When you show homes ask for feedback as you go. Note the buyers likes & dislikes. Don't show any more houses that they've already said they don't like: neighborhood, size, amenities, amount of upgrades, etc.