IMO I would work from your home at first if you can. The overhead of a store can be the death of you and it will take you at least 6 months to a year to develop a client base. Make a website showcasing your selection and keep it updated. Be willing to cut people good deals to get them into the hobby. You really make money off the small stuff, this is where you can mark up a lot without anyone knowing it.
I agree the store must be clean and organized. I dont know how many stores I wont go to because I feel my tank will get stds just from me walking in. Its very discouraging to walk into a nasty store.
Last bit of advice, dont try and rush it all and dump a fortune into it. Go slow, if you need another frag tank, add another. Don't start off with 5-6 frag tanks if you dont need them. When you build your tanks/system make it upgradeable and slowly add to it, this will save you a lot of money and will allow you to grow as needed.
Hope this helps.