Put in 10 hour days and I'm sure you'll still start to make some sales. Depends where you live as to if you can do it full time, you'll be fine if you live somewhere really cheap like Poland or Ukraine
To maximize chance of success one needs to research the keywords in the chosen niche carefully, see what the potential is before investing all your time. This guy does a
quality job on the cheap and can help if you other questions, he's helped me a lot.