I did Halloween parties for the kids at school. Here's some of my ideas that seemed to go over pretty well:
Eyeball soup(Punch). The punch is a big container of hawaiian punch and half a 2 liter of sprite. Then you have a bowl of gummy eyes to put one in each cup(see through plastic).
Bloody Hand Soup(punch) freeze a rubber glove filled with Hawaiian punch. Then mix white peach grape juice with sprite and float the hand on top.
My punch always goes fast so keep lots of refill supplies.
I make labels for all the foods(skin flakes-potato chips, mummy fingers-crescent wrapped mini sausages, ghost poop-chex mix covered with chocolate peanut butter and powdered sugar, etc. ).
Tons of food-you can never have too much food! I love doing Mummy fingers which is the crescent wrapped mini sausages for kids.
Decorate- rubber rats, giant spiders, trick or treat buckets to hold everything from chips to candy, cotton spider webs.
Prizes- start now with buying prizes to stash away because everyone wants a prize. Not stuff like spider rings but those $1 boxed candy treats or funky pens, slime, big gummy snakes....good stuff.
I made up a set of Halloween Bingo for the kids to play then gave it to the teacher for future years to come.
Good luck. I'm not even particularly fond of Halloween but teachers would try to grab me to do their party before someone else snagged me