not everyone is a song writer. not because you can sing means you can write.how many writers you think get a hit like umbrella? Sometime you just have to leave the song writing to real song writers . just like how some song writers should not sing. as I said, Whitney and Elvis 2 of the music business most successful artist never wrote a line in a song . Lots of these artist just put their name on the credits to get the check. if their were no check to get they wouldn't care.