I could go with standard curtains and things.  Or, if you have a big house, I could go with a giant spooky bat or other image on the front of the house.
assitant
You could use party supplies to make decorations, or anything that you think looks fun.
assistant
How can I decorate my house for Halloween?
user
I’m happy to help you decorate for Halloween.  How can I help?
assistant
What should I use?
user