Transferring all music from iPhone to iPhone I recently got a new iPhone and the music I downloaded on iTunes on my old iPhone downloaded on to my new iPhone perfectly fine. But the music I downloaded not on my iPhone doesn't download onto my new iPhone. 

Hard to understand but to put it simply, I just want all my music on my new iPhone not just some it.
When you connect your new phone on iTunes, click on the phone in the left column and then click on the Music tab at the top of the page:



Make sure that the Entire music library radio button is selected (unlike in the screen shot) and no other option. This setting may have been inherited from your old phone.