I talk with a lot of Christians and most of them seem to think they know exactly what god wants. You might wanna start by finding the countless Christians on this site who think their opinion is gods opinion- they will be able to tell you the truth aka just whatever they think the truth is which just so happens to be gods truth.
If you believe in God, how do you know it's without his input? He/she is God and therefore omnipotent, so you would think God could put the ideas in your head and get you to start writing. Unless you don't think God is omnipotent, then do you really believe in God?
Nope. It takes more than believing in God to write a book about it. You gotta know God, and besides, there s a book written about that already, well, a letter. the first letter of John. Plus the first chapter of Romans and the fifth chapter of Galatians.
Not really but it sure hasnt stopped hundreds of others from doing it. As ling as you present it as opinion and not foregone fact then theres probably no problem but if you present yourself as speaking for God Himself that may not turn out well.
Just depends. Just because someone believes in God does not mean they hear from God. If you don't have a personal relationship with Jesus then what you write concerning what God wants from us will only be your opinion.
Go for it. People do it constantly anyway, and if you are waiting for a green light or input from god, it's never going to come, so you are good. On this topic, you are just as qualified as anyone else to speak for god.
It worked for L Ron Hubbard, and John Smith. Now imagine if one of these were backed by the most powerful empire in the world and made the state religion while at the same time seeking out and destroying all other religions. In a thousand years everyone would be following Scientology and preying for UFO's to arrive, or we would be Mormons awaiting the afterlife when all men get their own planet to populate.