Having an MBA, or ANY other degree for that matter, is only as good as the person holding it. What you NEED to do is just get out there and 'Get Er Done, Son'...
Seriously, you do NOT NEED any other form of training other than EXPERIENCE. If you want something bad enough, then you should be willing to do anything you need to do, including the old "Try and Try Again" adage.
Get out there and do some research to see what IS working for your precise market/niche. Once you have that knowledge USE IT until it doesn't work anymore. Once it stops working, do some more research to see what is working then and USE IT until it doesn't work anymore. Once it stops working, do some more research to see what is working then and USE IT until it doesn't work anymore. Once it stops working, do some more research to see what is working then and USE IT until it doesn't work anymore. Once it stops working, do some more research to see what is working then and USE IT... get the point?
I would love to be able to give you a more detailed and informative response, but your question was very general in nature, so, unless you provide more details, my advice is (and will continue to be)... just get out there, get started and see what works for YOU... No one else, and no degree, can EVER dictate your success... Hard work, determination and self-discipline can AND WILL...