Also a help is find the original artist doing the song live and compare it to the studio version to see how much liberty they are taking against that studio version.
The term "liberty" implies that the studio version is some sort of reference, and the artist is seeing how much they can "get away with". Anyone who's ever done anything in their life more than once will (if they think about it) eventually come up with a better way of doing...whatever that thing is. The studio version is the start of the tune - that's what it was when it was an infant, hopefully with time it matures and gets refined.
I play church gigs. We're (in some ways) a cover band - except, of course when we're doing original material (I work with several folks who are songwriters). Anyway, if you listen to the live versions of worship tunes, they are often refined from the studio version - they use their experience and expertise to come up with ways of doing that tune that work better, or...fit the vibe better. I often play the same tune in multiple places, with different musicians on stage, and different things going on around us - audience, lights, tunes that ran before and after the one we're doing at the moment, and the topic of the message that's going to happen in a bit. Given all those variables, if I play the exact part that was "on the record", it's not the right thing to play most of the time - it doesn't fit what's going on around me most of the time.
When we do original material, there is a "record" as well, but sometimes the person that played the original bass part is on stage with me - playing guitar. He wants me to come up with a better part - he realizes I have more experience on bass than he does (he's half my age) , and appreciates what I come up with. The studio recording is a place to start, not the end in itself.
