How do you manage several online businesses and still achieve success?

I see a lot of people combining so many businesses together either online or offline. What amazes me is how they successfully manage all these businesses without failing.

I'm poor at managing so many things at a time; it's like chasing two rats which will eventually escape. If you have more than one business and you're doing well, please, I'll like you to share your little secrets with us to learn. Thanks