As tired and banal as these clichés may sound to you, the reason why they are clichés is because they are true.
The decision to buy a house is not solely based upon rational factors such as price, location and accessibility to services. It is also an emotional choice. It is a search for a home, a place in which one will find comfort, security and happiness, a place one would want to settle down and live in.

Emotions are set early, so it is important that minor, even typical, nuisances such as an un-mowed lawn or a pile of boots by the door are looked after. As unfair as it might be to your home, after only fifteen seconds most buyers have already developed a perception of your property that will color their feelings for the rest of the showing and perhaps dramatically affect their perceived value of the property.

• Plant flowers, weed and edge gardens
• Mow lawn and trim hedges and shrubs
• Clean driveway and sidewalks of dirt, leaves or snow
• Water the lawn extensively, well in advance of selling
• Remove old lawn ornaments, toys and play sets
• Clean and repair rain gutters and siding
• Touch up exterior paint
• Clean out garage
• Pick up any litter

• Make mirrors glitter and appliances sparkle
• Wash and polish all floors
• Clean and freshen bathrooms
• Clean/shampoo all carpets
• Clean all windows, walls, doors and trim

• Clear all countertops
• De-clutter all heavy traffic areas
• Store surplus furniture to reduce feeling crowded
• Put seasonal clothing into storage
• Clear halls and stairs of clutter
• Make all closets neat & tidy
  (and only half-full, even if this means moving items to another storage area)

• Touch up interior paint and paper
• Repair cracked plaster
• Tighten door knobs and cupboard latches
• Oil any squeaky doors
• Repair leaky plumbing (taps, shower heads and toilets)
• Repair seals/caulking around bathtub and sinks
• Replace burnt-out light bulbs/install brighter bulbs
• Clean furnace and humidifier
• Repair any other minor flaws

• Turn on all lights
• Open all drapes in daytime
• Play quiet background music
• Turn on air-conditioning or light fireplace
• Keep pets outside during showings (or, better yet, at a friend's)
• Have as few people in the house as possible. If you can, be absent during any showings
  as potential buyers often feel awkward and rush through if they think they are inconveniencing the owner.