IForge Iron has a subforum
http://www.iforgeiron.com/forum/45-the-business-side-of-blacksmithing/
It's about business and blacksmithing. Bit the advice there translates accross well.
I had my own plumbing business for 4 years before going back to school. I'm contemplating either buying into an existing company, or starting my own.
The name is most important when starting. After building a reputation it's secondary to the service people learn to expect. In all but the largest markets, repeat clients are the lifeblood of most businesses like yours. A website that is well set up with good SEO support is key too.
Personally, I prefer the commercial side of the business. More repeat business, less advertising costs. Your idea of targeting restaurants is good. Set simple pricing helps too. $1.00 per inch maybe?
Doing something you WANT to do helps. Do you make many knives? Kitchen knives? Just curious mostly.(that Hitachi would be cool to market!) It would be good if you do get your name in the kitchen knife community like Butch Harner has.
I'm putting together a business plan myself now. I've been plumbing for 16 years now so I have a good knowledge of what's needed but putting it on paper makes you face the cold hard facts and let's you
make a logic based plan(nothing wrong with winging it if you are able to take the risk).
I hope this works for you. Maybe stop at a few restaurants and ask a few questions about their knife
sharpening needs?
Good luck! Let us know what you do!