My thoughts for you:
Do you own your house? If not, will your landlord OK you selling guns there?
Do you plan to operate business in your house?
ATF can and will search your entire business premise at times. It is wise to think of where you will operate and have that setup prior to applying for the FFL. If you want to operate out of a rented house, talk to your landlord before the ATF calls for their permission.
In addition, if you're doing any manufacturing, contact OSHA and the local FD for any permits pertaining to hazerdous material (black powder, primers, etc).
For the taxes, etc. Setup an LLC and have a business license. It will show ATF you aren't just an "internet dealer" and it will make state\fed taxes easier to manage.
Talk to your references before submitting your app. If you have friends or relatives that joke about you being a "gun nut", don't use them as references.