I'm doubtless in a minority but I don't ever try to slavishly copy anything. To my mind, covers are versions of songs whereas tribute bands go for the 100% authentic approach. To that end, I usually listen to a song, noodle along to it, try to find something that sounds OK. Then I listen in more detail to the track and find bits that I like. Then I mish mash it up together, some of it original, some of it improvised. I'd find it extremely tedious trying to get every note spot on not to mention a bit sterile. Never had any complaints.