Write what you know is the advice writing instructors give to their students.
"But I don't know anything," I used to lament whenever I heard that statement. "What can I write about?" It's taken the Lord a lot of time and energy to help me realize those lies of the enemy firmly rooted in my mind since I was a young person.
For example, I find myself believing that the things I know are common knowledge and not important. But God keeps reminding me that things I've learned and take for granted, may be totally new concepts to others. Seeing it from His point of view really blows me away.
I've done children's ministry for so many years, it is easy for me to look at an object and immediately come up with several uses for it. I create weekly lessons and scour the Internet for craft ideas which I routinely adapt to my needs, sometimes coming up with entirely new projects or new ways to put those ideas together.
When I share my ideas, I routinely get positive feedback. If I would only write them down, I'd have a Christian education idea book ready to publish this very moment and probably a large audience for it.
He is a God of unlimited creativity and in spite of my insecurities, He gives idea after idea after idea! Thank You Lord.