Writers have an abundance of resources at their fingertips: books on writing, classes, blogs, other writers, conferences, seminars... the list goes on. If someone asked what writing tool has been the most helpful for me, I would say God.
It might sound sacrilegious to say I'm using God for anything, much less as a tool, but hear me out.
God is the greatest creator. The Bible says we're supposed to be godlike. Ergo, I believe He wants us to create. Whether it be something as important as children or something as unassuming as writing a novel, He is invested in not just our happiness but our success as creators.
When we look at it that way, it's easy to feel greater confidence in our writing. We have angels rooting for us. They cheer when we complete projects. On the reverse side, the Adversary wants us to believe we suck and we'll never be good at anything. Whenever you feel down on your writing, you can rightfully say, "Get thee behind me, Satan!" (Matthew 16:23) This outlook gives us purpose, and purpose is the greatest motivator.
But there's more to it than that.
Starting my writing sessions with prayer and scripture study improves my work. It lifts me up above my problems and insecurities by giving me more of an eternal perspective in my life. It clears my mind and inspires me.
There's more to it than that, too.
When I say God is a writing resource, I mean it in a very literal sense. Not only does He want me to write, but He's willing to assist me. I notice when I pray for help in writing my novel, I'm guided to the right beta readers, helpful blogs, useful books, and other things that make a world of difference. Things I have trouble with will suddenly click for me.
I don't believe He makes me a better writer; that's work I'm supposed to do on my own. I believe when I ask Him, He helps me with the things I can't do by myself.
If you're religious, I highly recommend using God as a partner in your writing. If you're not religious, He's there if you change your mind.