It's also useful to watch the refs and see how they 'conduct' the fight, how the promotion likes to announce people so you can plan your entrance lol, and various other bits and pieces, these days judging does tend to be by people who know what they are doing and often you'll see the same judges at different fight nights so have an eye out for how they score. Judges do have preferences on how they like to see a fight going so it's useful to know.
I'd suggest watching a potential opponents fight videos before agreeing to fight though that's really your coach's job, you watch it after they've agreed the fight. As I said before watch fight videos critically, as if you were judging not as just a spectator, it does take the enjoyment out of it a bit but this is part of preparation. You may learn a move or two watching fight videos, but you actually have to know what you are doing (ie have a lot of training under your belt) to take advantage of watching techniques in fights, definitely not for beginners.