When I first started mixing I actually never started by listening to the
original. The direction of the completed track can potentially taint you
into doing something a certain way. I would say listen through the
multitracks until there is something you like and start with that. Then put
the next thing in you like. You can also inerject whatever you want from
wherever else to it too. The idea here is to make this sound like something
you want to hear.