Before our guests arrive, I prep as much as possible and always load all of the pots and pans and assorted dirty dishes into the dishwasher so that I can run it during the party. I also set up my mise en place and lay out the serving dishes. (In the photo above, you can see that I have the plastic chopping board and all of the ingredients out for my miso-glazed brussel sprouts; the wood cutting board out for the roast chicken; and the salad bowl and tongs at the ready.)
For foods that need reheating or finishing in the oven or stovetop, I like to put a post-it with the oven temperature and heating time on the dish itself. This way I can put away all the recipe books ahead of time and have all of the important details at the ready.
For occasions like Passover and Chinese New Year, when a meal is going to last a looooong time, we use this relatively inexpensive chafing dish to keep the food warm.
As you can see, I also try to do much of the set-up in advance, so that all I have to do the day of is finish making the food and placing it on the appropriate serving vessel.
I'm afraid that these are all the tips I know. What are your favorite techniques for keeping everything organized and delicious for a dinner party? Please share!