I don't know how to utilize melodies enough to make a song beyond maybe 2 minutes 45 seconds.
I don't know the basic "science" behind music, and I don't know any theory. I just play things by ear and put things together based off of what I know rather than what is proven to be right. I'm taking a Music Theory course next year as part of my Senior year of High School, so I'm hoping to learn a lot in there.