Oh yeah, don't forget a business plan. The top reason most business ventures fail is because of a crappy business plan or lack of one to begin with.
I attempted a "business" venture last winter, and tried to do it on the cheap too, and failed. Since I did it on the cheap, all I lost was a very negligible amount of money and a little bit of time.
Now that I have had a little more training in the business field, especially from reading books (I've read about 7 books so far about management, marketing, accounting, and even communicating effectivley), I can see why having such training is important. I now see where I went wrong, so next time when I start a new business venture (probably around next summer) I will know how to make it a success.
Also remember, if you're serious about this business, put money into it. Yes, you can get a lot done for free, but paying for stuff like advertising is KEY. Don't settle for one type of ad using one type of medium. Spend the extra couple of hundred bucks on a newspaper ad or fliers, perhaps a billboard (they're cheaper then you think - a full month in Chicago on a busy street costs around $300). Of course using the right medium depends on your audience. For example, don't advertise a hosting company in a residential area - go for the business sector. And don't advertise in a Children's magazine, go for a computer-related or small-business related one. It's all about marketing, a topic I suggest you research before doing anything.
If you aren't serious enough to put any money into it, don't get your hopes up about any potential profts; they won't arrive. You have to invest something to get anything.