Make it light and bright.

Make lighting in your home the "welcome sign" for homebuying prospects.  Please turn on all the exterior and interior lights, including accent & picture lights.

Avoiding the crowds.

If there are too many people around during the showing, potential buyers feel like intruders and want to hurry through your home.  Take a nice drive or a walk with the kids while your house is being shown.

Shhhh!

When your home is being shown, have all TVs turned off.  Turn the stereo off, too, or put on soft, mellow music.  Let prospective buyers and their agents talk calmly without having to yell over any noise.

Having pets around the house...

...is wonderful, except when showing your house.  Take the pets out for a stroll, or have them kennelled during showings to avoid any uncomfortable "meetings" between your pet and strangers.

This is not a social call!

If you're present during the showing, be courteous and friendly, but don't force conversation with potential buyers.  They are there to inspect your house, not to be social.  Let the showing agent do all the talking.

Nor is it a garage sale.

Don't try to sell potential buyers any of the furnishings that you don't want to take with you.  They haven't even bought your house yet.  It could jeopardize the sale.  It is an option to have a framed list on the kitchen counter of all items for sale and their prices.  This comes across much less agressive, and allows the potential buyer the option of bringing it up in the sale.

Trust your agent to do it right.

Let your selling agent negotiate with the buyers about price, terms, possession date, etc.  They have the knowledge and experience necessary to get you the best deal possible.