Never leave this extremely important stage till the day of the party itself, otherwise you'll be too preoccupied to concentrate on making yourself look like the hostess with the mostest.
Start by having a long hot bath - a bit of relaxation will do you good after all that organization! Pamper yourself with a face mask, an exfoliating scrub to polish your body and a hair mask to get your locks in tip-top condition for the party. Leave masks or pampering products on overnight and you'll be glowing and shining come the big day. If you have long hair, blow-dry the night before to give your hair time to set.
Think carefully about what to wear. As the hostess, you're going to be doing lots of running around, so go for something flattering you feel comfortable in.