2 tbsp. chili powder
1 tbsp. paprika
1 tbsp. cumin
1/2 tsp. garlic powder
1/2 tsp. onion powder
1/2 tsp. black pepper
1/2 tsp. celery salt
1/2 tsp. salt

As with anything, tastes vary. So test, then improvise, adding red pepper flakes, a little sugar, more or less cumin, etc.