Dinner Party Checklist

Three Weeks Before

Choose a theme, if you want one.
Decide whether it will be an elegant soiree or a cozy supper, then think about a theme in terms of season, occasion, and guest list. Make, buy, or borrow any related decorations you might need.
Extend invitations.
Mail, phone, and e-mail invites are all acceptable; the more formal the dinner, the more appropriate a written invitation, perhaps tied into the theme. Include such details as the date and time (typically 7 p.m., which allows an hour for cocktails, appetizers, and mingling), the deadline to RSVP (a week before party day), your address, and suggested attire if formal.
Plan the menu.
Keep it fairly simple, including make-ahead dishes if possible (so you don't spend too much time running in and out of the kitchen), and take the weather into consideration.

Two Weeks Before

Come up with a playlist.
It should be long enough to last for the duration of the dinner, coordinate with the party's theme if there is one, and be kept at a level that doesn't hinder conversation.
Clean any crystal, china, and silverware you'll be using.
And launder and iron linens.

One Week Before

Clean the house thoroughly.
To maintain it for the rest of the week, do a quick daily routine.
Take inventory of tableware, cookware, and serving dishes.
If you don't have enough for every dish you're serving, consider purchasing inexpensive pieces from a discount or thrift store or borrowing—don't be afraid to mix compatible patterns. Allocate a serving dish for each menu item, and label the dish with a Post-it note.
Make a detailed shopping list and cooking schedule.
Map out where you'll buy each ingredient or beverage to streamline your shopping route. Rule of thumb: Calculate three bottles of wine for every four guests. Place an order with the local butcher, fish shop, baker, or liquor store as needed.
Set the stage.
Arrange the furniture as you'll want it for the party, checking for the flow and removing any clutter. Designate a coffee table or side table for coffee and dessert if you wish. Figure out the lighting: Using low-wattage bulbs or candlelight will create the right mood.
Create a seating plan if desired.
Mix together people who aren't familiar with one another, and set out placecards.

Three Days Before

Decorate.
Lay out all decorations but the flowers.
Check the medicine cabinet.
Remove any personal items you wouldn't want guests to see.
Designate a place for coats.
Make space in a front closet and fill it with hangers, or designate a bed for coats (and make sure the room's especially tidy and clear of valuables, so you won't need to worry about them).
Shop for food and beverages.

One Day Before

Set the table.
Buy flowers.
Arrange and set out around the house.
Do as much of the cooking as you can.
Also, for any foods that require cooking on party day, do as much prep (dicing, marinating, rinsing lettuce, etc.) as possible.
Make a sweep through the house.
Do cleaning touch-ups where necessary.

Three Weeks Before