I have started about 7 new businesses, that either were sold, sold partnerships out, etc. and am currently in four businesses that are up and running as we speak.
Passion is key as mentioned before - otherwise obstacles get under your skin and you will be working with that second choice thing in front of you all the time.
The other thing, one business up and running can greatly help fund the next, but only when you are going strong. . I would know and it`s REALLY tough to divide yourself if your first business isn`t in tact and run by someone that values it as you do.
Then maybe some other investment opportunity that has some ROI that won`t demand your time so much could be next - . Loral Langemeier calls it the Wealth Cycle.
The other thing - get a business partner or an amitious marketing/sales partner to help you. When you get up and running, then you have the thing called TIME that gets to be trickly. Always plan for it to cost more than you ever imagined to get going, so watch expenses as you go, don`t reinvent the wheel, and be sure to ask a boat load of people who are doing what you want to do but are already fabulously successful that will give you advice as to how to start and avoid their mistakes they made.
I follow a good bit of Loral Langemeier`s info at www.liveoutloud.com and her info rocks the house with great advice, counsel, and her books and cds are great to reference when you need.
Anyway, I hope you do really well. When ever you need help with marketing, I have invaluable resources to reference to help boost sales and then some.