how to start a small business

I have the person to make the site, some suppliers. I have never own a business before and tought starting an online Business might be a little less expensive than an actual store.
Any places offering some kind of training? how do I make my site known?

Please help! I need suggestions, links, ideas, etc if you have an online business tell me if you recommend it as my first business.

PS: Ebay is not an option for me.

If a person wants to start his own business in mid of his career and quiting his job, what are the safe business ideas for that? How additional funding can be obtained, except direct loan from any institution.

And how stingy can you get? I’m a Pilates trainer, but I also need to have training sessions at least twice a month to keep myself aware of what I’m teaching others. Could this be counted as a business expense? Or if, for instance, I only wear makeup when I go to business meetings (which is true), and not for everyday things like going to the grocery store, can I write it off as a business expense?