For most people, last year's tax return is a good starting point, but it is just that, a starting point. If you have 2016 sources of income, such as a job that provides a W-2, and you will still be working that job in 2017 in addition to starting your own business, be sure to bring those income amounts forward.

Next, you need to estimate what your income from the new business is going to be in 2017. If you have a business plan, that will be a very good place to look for those estimates. If not, you may just have to make an educated guess, based on what you know about the goods or services that you will be providing, whether you will be working full- or part-time, your costs and selling prices, etc. Keep in mind that the amount you will enter into TurboTax is net self-employment income for 2017, that is, your gross receipts less your cost of goods sold and all other business expenses.

To prepare your estimated taxes for 2017 in TurboTax Self-Employed, click on the Personal tab, select Other Tax Situations, select Form W-4 and estimated taxes, and complete the interview.