It's never bad to be overprepared! IMHO, the first thing you should do would be to find out the legalities in your country/state/city/county. It varies so much - you may have everything you need to open up shop or it may be next to impossible in your town. I would start by contacting either your local health inspector or get in touch with your state's Dept. of Agriculture. You really don't want to miss this step. Lots of venue's will require that you show your health/food license before you can even deliver a wedding cake there. Bridal shows are also starting to require it too of food vendors, since you'll be giving out free eats at the show.
I'm a one-girl (OK my hubby helps part-time), fully licensed bakery and I keep myself busy doing nothing but wedding cakes. I have been in business about 7 years - it didn't start out that way. You get there my building your business and reputation. I have had employees, and honestly, I like working better by myself. When I compared the extra money the workers brought in compared to their wages, it almost always was a wash.
If you do a bridal show, and you have a good product, cake orders will start coming in. Make sure you are ready for them. Bridal shows should start very soon (usually January). Either pay to go to one, or contact the show promoter and get a free vendor pass (as just a visitor). Take your camera and notepad. Take pictures and notes of what other people are doing. Don't limit yourself to just the cake booths either; Photographers usually have the nicest, most elaborate booths!
I took some Small Business Admin classes from the local college, and they were somewhat useful. They talked a lot about business plans and such, but they also told us no one would lend us money based on a business plan. For (our) small businesses they said prepare to put up your house as collateral for a business loan. These are my experiences and others may have had different ones. Your mileage may vary!
Best of luck!