This party can be had for the adults as well as the kids. But it is a fast that kids enjoy it better. If you are having it for adults you can make it a bit more spooky and if it is for the kids then you can go easy on the scary things.
First of all your invitation must be quite scary.
You can draw a picture of your house with a spiders web covering it and give details on the party and how to dress. Your decorations must all be related to the Halloween theme. Paint your feet with red paint and make footprints leading to your house. Keep it dark inside. Make witch brooms and hats and hang it all over. Get some white thread and hang it all over the house as dust.
Play scary music all through the party. Pour coke in to a big vessel and throw in some plastic insects for effect. Name all your food items according to this Halloween theme. Call them witches stew, bloody pizza and things like that. Once your guests start coming make sure to click photos and play games like dressing the mummy .
Have a fashion show and give a cup to the best and dressed. The prize can be a cup which is held by a skeleton. If you have got kids over take them to your neighbours house for trick or treating. Inform them that you will be coming so that they can keep bag of goodies ready.
Hide some plastic insects on the fan so that when you put it on they fall down and your guests get the fright of their lives. If you do not have pumpkins or jack o lanterns you can use small capsicums instead. Your return gift should also be according to the theme chosen.
Get a few magic tricks as return gifts or things like swords and teeth with blood on them. During the party make sure you play a round of dark room with eerie music in the background. Remember you should be the best dressed for your party.