No one will respect you or take you anymore serious than you take your self. Remember, the first professional of any trade was just serious enough to the point that no one could deny what that person stood for. So how can you demand to be taken seriously if you don't take your self seriously? You don't. That's why you'll never get the respect or the pay that you deserve.
This works now, but I wish I had known this as a kid! Maybe Mahatma Ghandi can translate for us - "“Be the change you want to see in the world.”