Thats a tough one, I worked full time but I already had 2 clients before I gave my notice. It was extremely hard, I had to use a lot of my vacation and sick days and also my lunch hour when possible. If you can do it, I would say get as far as you could with the start up of your business but when you begin starting your marketing make sure you use your cell phone number for marketing purposes so that you can be available when possible. I won't say it's going to be easy because doctors are not going to want to leave messages when they are shopping around, what I did was have a message on my cell phone that I was on another line and would return their call as soon as possible.