I found a site that gives good advice on shooting Halloween videos, it's called Halloween Photography and there are tips for shooting photographs as well as video. Shooting, lighting and such. Some special effects ideas can be found here. And here is a good video that explains an easy way to make latex appliances for the face. Here is her site. I like this plan because it doesn't require several steps to make molds and such:
As mentioned in an earlier post you can find costume ideas ands props at a party store or in just about any department store till October 31st. Most of these ideas are not expensive to make and use. Check out the video above and have fun!