Prepare popcorn using oil with preferred method. My Basic Popcorn post has more information about popping and about my favorite stovetop popcorn popper. Air popped popcorn won't work without additional oil since the seasoning needs moisture from the oil in order to adhere to the popcorn.
Combine all spices, and salt in a small bowl.
Blend seasonings in a spice or coffee grinder, or blend in blender to make a fine powder.