Expect problems and eat them for breakfast.
To know oneself, one should assert oneself.
If you can dream it, you can do it.
Who seeks shall find.
Quality is not an act, it is a habit.
If you've got a talent, protect it.
Always desire to learn something useful.
Be gentle to all and stern with yourself.
You never know what motivates you.
What you do today can improve all your tomorrows.
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.