Well, I listen to more bands than soloists, so I kind of read up on the band's history and what not and get all their songs (if I really love them, otherwise I just get some of their songs). I also try and make sure I understand what each song is about (otherwise the band's message won't be getting across to me, and I won't be able to judge how well they've said what they wanted to say, musically and emotionally) Mostly, though, I tend to find out as much as I can about the singer of the band (I tend to get really obsessed with singers...) It's probably 'cause I sing myself, and because they're (generally) the face of the band and are damn good vocalists. I have a soft spot for keyboard players too, as I play the piano. With guitarists, bassists and drummers, though, I never know how to judge how good they are, so I just take them as part of the band, and as long as they can play that riff/beat I particularly like well in live videos on YouTube, I'm happy.