Only the educated are free.
Never complain and never explain.
Know or listen to those who know.
If you can dream it, you can do it.
Problems are not stop signs, they are guidelines.
If you think you can do it, you can.
Expect problems and eat them for breakfast.
Either you run the day or the day runs you.
It's always too early to quit.
Be gentle to all and stern with yourself.
There's obviously nothing wrong with selling your art - only an idiot with a trust fund would tell you otherwise. But it's confusing to know how far you should take it.