One of the great hazards of running a home based small business are the benefits you get from full time work for a conventional employer. Why are they a hazard? Because they'll convince you that your business needs to replace the money and benefits you'd make now with what it can pull in. This is a hazard, because it keeps more potential small business owners from starting their business at all.
The key is to balance the two and make a staged transition. You can work full time at your existing job, and take on some part time work for a home based small business of your own as well. This has several advantages.
First, you're not giving up the steady paycheck of the day job, nor are you giving up the automatic tax payments that come with it. Several professional writers and novelists keep a part time job working in retail exactly for these benefits - the retail job will cover their bare bones minimal financial needs and will, by minimizing the number of deductions taken out, generally cover the money they make from writing novels for reporting to the IRS.
Similarly, working part time on your own business lets you learn the ropes in small steps; you can find out who your preferred clients are, what kind of work you enjoy doing in this field, and work out if the business will ever cover your expenses entirely. Most small businesses are quite functional as part time endeavors, and the extra income is often used for things like paying off credit card debts, or paying off a mortgage a bit more quickly.
If you do decide that you can take your part time business full time, use the last year or so of part time work building up a 'nest egg' before going full time. Use it to pay off personal debts, or business related debts. Focus on paying down debts that will look 'bad' if you're going to apply for a Small Business Administration starter loan.
When trying to run a part time small business, you may also find some support in unusual places; many companies will encourage employees to start up small, non-competing businesses. This tends to make for better employees as well, since they understand the full ramifications of running a business and all that entails.
You may also be able to get some flexibility in your work schedule, such as working four ten hour workdays to have a weekday free to talk to your own clients. (Even better, many jobs will let you work Sunday through Wednesday on that sort of schedule, giving you two weekdays free to concentrate on your business.)
Regardless of how you start the path of owning your own home based small business, understand that by working part time, you can take it in stages, and let your business grow at the pace that best suits it and your family.