Make sure you have at least two non-alcoholic drink selections. Also, you don't need a vast array of liquor; just have a few bottles of higher end spirits. Avoid serving red wine. Opt for a dry white and a sweet white instead.
If you don't have glass top cocktail and end tables, make sure you have plenty of decent-looking coasters and white cocktail napkins. You can use a nice tray to protect your cocktail table as well.
The food should be bite-sized and well-presented. Even simple fare should be presented with care. It's a good idea to limit the number of hors d'oeuvres, and it's a great idea to serve a few items that you can make in advance.
Make sure your home is clean and that your bathroom is stocked with enough tp and several nice hand towels for the evening. A lit candle in the bathroom is a nice touch. A small, simple floral arrangement is nice if you have room. A white arrangement with dark, waxy green leaves is a nice choice because it looks crips, and it's not overly feminine.
The most important thing is to be relaxed and gracious. Your guests will follow suit. Have a great party!