You're asking a classic question, that all new business folks struggle with when they start. And seriously, again, all new business folks, not just folks that may happen to frequent this board. Muse's comment is correct:
It sounds like you are most concerned with reporting income and paying taxes. If that's the case, go to a CPA and they can help you set up you books. Most people call it a consulting business, etc.
Originally Posted by Your Naughty Muse
The key issue is simply finding someone (CPA) you can trust, that can help with the tax stuff. I'm sure that you'll get a pm, or two, or dozens, with help offers. But seriously, you should find a tax person (CPA) in your area. Otherwise, the logistics of dealing with tax paperwork, even once a year will be a pain.
Some folks do create their own business (consulting, house sitting, dog walking, etc.)with a business name, checkbook, etc. Some don't. Some think it's helpful for assist staying UTR. Regardless, if money is used for rent/mortgage/utilities etc, you really need to have a source of income that is taxed. Thus, the discussion is back to finding a tax guy/gal (CPA).