Generally the rule goes like this. If the birdy is moving away from you, you look at the opponent. If the birdy is moving towards you, you look at the birdy. Heres the question. What do you look for when looking at your opponent. What part of his body or racket?
If this is an opinion this is what I usually do: On Serves I look at the racquet face. If they're smart enough to mask this obvious position give away, then next I look at his body rotation. I look for what direction he is facing to see the potential flight path of the bird. This is because if he were facing me, it would be more difficult for him to cut the bird to make it drop at the far corner. The last thing I look at is the eyes of the opponent. I look for where he is looking at and try to catch quick glimpses of where he may try to place the bird. On Net shots (such as the opponent running up to drop) Throughout the game, I always look for how much the opponent will use cross-court shots to determine whether he'll make another when I run to the net. Now, most of the time I do forget lol. But when I'm at the net, I keep my racquet up and watch his body rotation firstly. I look at what angle he/she is attacking the bird at and then look at their wrist and the bird. I refuse to look at racquets when at net shots because a turn of the wrist or rotation of the hand can quickly change the way the net shot is played. The Wrist give away the speed of the shots and when I see this, I can guess how much power needs to be given to get to a certain position over the net. So if it were a strong wrist motion, I'd assume it be a cross-court shot while a very stiff wrist would probably be a hit back to me. On Clears for opponents smash/drop I haven't yet really found a solid way to read this type of shot, but it's more of an instinct. I have to wait a split second to see how he hits it before I move. So in a smash, the obvious sign is that the racquet comes down at a quick speed. At some instance, I follow his body rotation as a trigger to tell me he is smashing. The same thing happens in watching a drop or cross-court drop/smash. A split second before the opponent makes contact with the bird, you have to carefully watch the racquet positioning as in whether the racquet is coming straight down perpendicular to the ground or around-the-head at an angle to the ground. I also look for the racquet speed change when I do this. The difficulty reading these shots is that you have only a small window of opportunity to gauge where the shot will go and it isn't really a read on the opponent because they can be very deceptive of it. You don't necessarily have to follow what I said, but this is really what I do when I am given these situations.
I try to avoid second-guessing my opponents, because it only works with the weaker ones. Against better players, I can lose a rally (especially in singles) if I try to read them too much. It's different when I can see they are under pressure. In these cases, I often know that they are not capable of (say) a clear or smash, so I will move forward. I never try to read the serve, because even some of the weaker players have deceptive serves. I just look for the shuttle.
