Troy: Cali no doubt has stricter requirements - but you don't actually need commercially zoned property and a storefront, at least not according to federal requirements.
To have an FFL, you must have a premises from which to conduct business - that means a commercial storefront OR unzoned property OR a zoning/use waiver/variance. If you don't live in a city, or your house is zoned multi-use, then you can do it from your house.
You must conduct your business in accordance with the law of your city/county/state - this usually means a business license, sales tax license, etc. If you have a premises from which to conduct business, you can get the required licenses. I know Cali has their 'certificate of eligibility' crap, so this may not be possible there.
You have to have 'safe storage' which need not be a safe - just trigger locks or some form of locking storage. Putting a padlock on a hall closet is sufficient.
It's much better if you have a separate outbuilding (e.g. garage or cabin) from which to conduct your business, though, as the ATF is free to inspect your premises during your listed business hours.