Now, I work more than ten minutes daily, but that's by own choice and because I want to do a lot of different things.
Writing fiction is one of them.
The main part of my income comes from an activity that takes me ten minutes daily to do. Sometimes even less.
It's writing emails.
There are rules you must stick to, and there are things you must do, just as there are things you must never do.
I share it all here http://malka.biz/writing-better-emails/