For a large cocktail party, invite 20 percent more people than you can fit, since typically only 70 percent to 80 percent of invitees attend.
Make, buy, or borrow any decorations or music you may need to fit the theme.
Mail, e-mail, even phone invites are all acceptable.
Assemble the recipes (choose only those that can be prepared in advance, perhaps even frozen, with just warming and assembling required on party day). Make a list of how far in advance each can be made, and compile a shopping list. Place an order with your local delicatessen or bakery, as needed.
Consider hiring a high school student or a professional to help with pre- or postparty cleaning or to pass drinks or appetizers, replenish buffet food, tidy up, and generally take some weight off your shoulders.
This way, you'll need only a quick once-over before the party.
Arrange the furniture as you'll want it for the party, making sure that guests can move easily from one part of your house to another. Designate a coffee table or side table for coffee and dessert, if you'll be serving them. Tuck away things that will be in the way, precious items that might get broken (or even be taken), and any clutter. Figure out the lighting: Using low-wattage bulbs or candlelight will create the right mood.
If you don't have enough for every dish you're serving, consider purchasing inexpensive pieces from a discount or thrift store. Label each dish with a Post-it so you'll remember what you plan to use it for at party time.
Plan three bottles of wine for every four people, three to four cocktails per guest for a two- to three-hour cocktail party.
Let them know you're having a party if you expect it to be large, loud, or parking-intensive.
Arrange candles, put up theme decorations, etc.
Remove any personal items you wouldn't want guests to see.
Place a box of salt, Wine Away (red wine stain remover), club soda, and a couple of rags in a wicker basket, and store a few in strategic places in case a nasty spill occurs.
Make space in a closet and fill it with hangers. You could also choose a bed for coats (make sure the room is especially tidy and free of valuables, so you won't need to worry about them), or purchase an inexpensive portable garment rack.
Make a detailed cooking schedule for your remaining dishes.