Those types of statements may lead you to believe that you have to change your focus, your beliefs and ultimately who you are in order to be paid for your work.
Don't go there.
Should you take marketing and audience into consideration when you write that query letter - yes! But don't take it into consideration when you are beginning to write.
Creativity is an illusive mist. It comes and goes at will and you need to be prepared to make use of it when it appears and push through the desert when it's gone.
One of the traits of creativity is that it must be free and it must involve your own standards, beliefs and ideas. It must come from you. That's where all the passion and excitement is located - deep within you.
If you try to write another person's thoughts - if you try to be them - you will turn out miserable, unfeeling work. Your plan then, should be to write your passions. Get excited about your ideas and your writing. Don't consider the world or what they will think - be who you are.
Just don't forget the last step! When you are down to the re-writes, apply compassion, consideration and those marketing concerns. Don't betray the core of who you are but learn to "edit" so your reader can accept who you are.
Claire W. in God Help me Create says it this way....
"Only we can set standards that are appropriate and that help us in our work. If we try to adopt the standards of parents, family, or friends, we may lose all joy in the creative process.
We may also be hurt trying to please the recognized authorities or the critics in our field. However dependent upon their approval we may feel, adjusting our work to their standards will probably rob us of both pleasure in and respect for our work.
Essentially, the work we do is aimed at people who are like ourselves. The "audience" we try to reach, the "market" we try to sell to, is made up of people who delight in the things we delight in, who believe in the things we believe in, who are moved by the things that move us.
In setting standards, we must honor our own sense of what is right and good. If we do so, it is likely that others will recognise the integrity of our work and respond to it favorably."
Any man who will look into his heart and honestly write what he sees there will find plenty of readers. Edgar W. Howe
God loves you and has called you to write,