The casual cocktail party: a new take on an American tradition.

Many people love to entertain. But while they welcome the company, conversation and conviviality, most dislike the fuss and formality. For them, the '90s casual cocktail party with its easy, informal manner mey be the entertaining style of choice.

A generation ago, the words "cocktail

party" conjured up version of a slinky-gowned hostess, dinner-jacketed host and gleaming silver trays of gourmet foods. Today's cocktail party is a nofrazzle affair where the relaxed party giver has as much as the guests. Casual, however, does not mean haphazard or unprepared. It means being so completely organized beforehand that the party seems to run itself. Of course, providing easy pleasure is hard work, yet it must seem effortless.

A Party's Success Is In The Planning

The work begins with the invitation. State the time your party begins and don't be shy about stating the time it ends--6 p.m. to 9 p.m., for example. Although guests may linger for another half hour, it lets them know what kind of party it is, whether they should expect dinner and whether they should make other plans for the rest of the evening. At the same time, consider how many people you can accommodate. Casual does not mean crowde; it means confortable.

A significant difference in the cocktail party of the '90's is that fewer people actually drink cocktails now. Consider that when you're planning your beverages. Since more people are drinking wine, have on hand a variety of dry white wines---Sauvignon Blanc, Pinot Gris or Chardonnay--as well as such light reds as Beaujolais, Italian Merlot, Bardolino, Valpolicella, Swiss Dole or Merlot. You may also want to serve a lightly spiked punch. For those who abstain from alcohol, have sodas, bottled waters and fruit juices available.

Not everyone has turned away from mixed drinks. Be ready to serve up a classic Martini--stir 2 ounces of gin or vodka over ice, add a dash of dry vermouth, strain into a martini glass and add a green olive. Or, shake up a Rum Sour. In this case, pour 2 ounces of dark rum, squeeze the juice of one lime and add sugar to taste over ice, shake and strain into an old-fashioned glass and garnish with a slice of orange. A picturesque and handy reference guide is The Art of the Cocktail by Philip Collins (Chronicle Books, 1992; $12.95).

Have the basic on hand: a few bottles of fine spirits--gin, vodka, rum, bourbon and Scotch; a corkscrew, bottle opener, double-end measuring cup or two shot glasses (1 ounce and 1 1/2 ounces), and measuring spoons; a 16-ounce shaker, strainer, tall 16-ounce mixing glass, pitcher, long-handled sppon; and a bucket of ice, tongs, small cutting board and a small sharp knife for slicing fruits. Such garnishes as lemon and lime wedges and twists, orange slices, olives and cherries are cocktail staples. The bar should include such mixers as tonic water, club soda, ginger ale, tomato and orange juice. Behind the scenes, lay out a good supply of extra glasses, paper towels, dish towels and heavy duty garbage bags.

When it comes to food, keep it simple and easy. Serve platters of light finger foods guests can put together themselves, Serve nothing that needs to be cut, since most people will eat standing or sitting with a small plate balanced on their lap. If your party is scheduled to end after. 9 p.m., plan on more food, such as a sliced ham or pasta salad and one or two hot dishes that can be easily negotiated with a fork.

Now you're ready. The buffet is set. The drinks are chilling. Don your best pair of jeans and greet your guests. Jeans? At a cocktail party? Well, we did say it was casual.