Reply to how do you remix a song?

ok i know this sounds like a stupid question but here goes

Ok so i want to start trying to remix songs in live just wondering how you go about?

so say i find some pop song or what have you and i want to turn it in to a electro remix or dubstep etc... how do you go about it?

is it a case of putting the song in to live choping off the verse chours bridge then building a new song round it?

or getting just the vocal track and figure out what key its in and building a new beat...?

and what about if i want to remix an electro house track how do i go about adding more to it with out over doing it?

all so if anyone has any tips and the best way to get started with remixing a song in Live would be greatful cheers