I spent several years acquiring the obsessive, day-to-day discipline that's needed if you want to write professionally, then several more, highly valuable years studying fiction writing at the University of Iowa.
It's sheer torture. I have to be up with the chickens every day and go to work on my body. I hate it, but I do it.
For me, one of the important things about keeping vocally healthy is warming up and making sure I'm aware where my voice is at, drinking lots of water and getting plenty of sleep, and just taking care of myself with exercise and eating healthy.