Also not a tax expert, but here are the 2015 tax brackets: http://www.forbes.com/sites/kellyphil...
This will be based on your total income for the year, so if you're working other jobs that already have taxes withheld, you can deduct that from your total due taxes... I'd recommend setting your exemptions to 0 for any jobs that are already withholding taxes - this will tax you at the highest possible rate for your income from that job and will mean you'll owe the least amount possible at tax time. And as Rosie said, keep track of business expenses. If you're licensed and insured and operate out of your home, this can include anything from cleaning supplies to dog food to replacing carpeting or wood floors. If you're planning on this being a full time endeavor, consult an accountant so you know what you should be keeping track of.