I've just found out I'm a SBS winner this evening, my twitter account has since gone crazy, looking forward to seeing how this makes a difference :)
I studied design after leaving school but was then lured into sales with the promise of a good career, then after 8 years of estate agency work I decided to leave and follow my roots back to design, garden design to be specific. It was a hard move as I was a partner in a well known chartered surveyors by that point and ran the residential office however I'm glad I did it as there's nothing quite like running your own show. Three years on and we're growing fast, we now cover Landscaping and building as well as garden maintenance and lawn care.
Just go for it! (after some careful planning and contemplation). Plan everything as much as you can but dont be afraid of adapting and changing your plans when the results point you in a different direction. Know your business inside and out by analyzing results at every opportunity. Finally marketing is king, without customers you dont have a business.