This element of the party obviously varies to what holiday you will be celebrating, in this case, we're preparing for Christmas.  

Lights
If you have a party, always put up some lights, whether it be on trees or bushes or anywhere.  First of all, they look spirited and show that there has been an effort made in planning this holiday party.  They also illuminate the house so when the guests arrive, they will definitely know which house is yours.  But please remember this-- twinkle lights are nice, but they can be TOO MUCH sometimes.  Remember you want people to come and stay at your party, not be afraid of your house.

The Tree
There is only one time a year where you can have a giant evergreen in your living room lit up with lights and ornaments.  This will put a smile on any Scrouge's face!  The tree is a very important element of your decorating plan.  If there are young children who still want their ornaments on display, there's nothing you can do to make the tree look beautiful and organized, unless you put those ornaments towards the back when they go to sleep.  But, the best looking homes have a color scheme on their tree, and then decorations that color coordinate to their tree.  The good thing about Christmas is that majority of decorations made will all look good together, so make sure your ornaments aren't pink and purple with orange lights! Then everything will fall right in to place.

Wreath
This is a small detail that is not a necessity, yet just another thing that puts people in the holiday spirit.  When arriving to your door, it is nice to have a lovely holiday wreath for your guests to admire as the await to come in to your house!

Everything Else!
Most of the people who attend holiday parties will always comment about how the house is decorated.  It doesn't take very much work, but to hang up a few things here or there.  Always have the fire place lit for it sets any holiday warm and cozy mood.  Therefore, if the fire is lit, hang the stockings, but a good distance from the fire!  Stockings are a tradition that everyone knows Santa is coming.  A dim lit house around the holidays feels even better lit by candles.  They bring out the light in anyone's heart.  But never forget-- the candy canes for people to grab on their way out, as well as the mistletoe.