When I listen to many older rock bands like queen, GNR, I notice that the music can sometimes change two or three times in the middle of the song like going through gears almost, its the same note played in a different key so that they sound ascending, or descending. I noticed this is a brilliant compostiotional tool/cheap trick whatever your perepective, but I would love to get a handle on how to choose key changes that work musically, rather than picking a random key and hoping for the best, where would I find what keys should work in terms of the key I start with?