Here's the thing about mindset and I'll use my own example. I am a lower order batsman, crap basically, so there have been days I have gone in thinking how am I going to survive this guy or that guy and avoid getting hit, well my brain tells me I am scared of getting hit so I need to watch the ball to avoid the pain. So I watch the ball, sometimes I am so focused on watching the ball that I forget to play a shot and like Silverbullet say, by the time I react the ball is already in the keepers hands.
Another thing I have noticed about my own batting is when I am trying to watch the ball, I see it in the bowlers hand, then come out very nicely but somewhere between release and ball pitching I lose it, most time just before the ball pitches. I think thats where Buzz has a good point about players like us looking down or worrying too much about other things like moving in the right direction or out of the way etc....now I tell myself to not just watch the ball but also watch the ball bounce...its the hurried movement to try and get to the ball or try to hit when I am off-balance and where my problems lie....
Anyways these are just my experiences, I am not a coach. Most days, when I go in thinking I can handle all of them but I just of have to watch for this one "guy" that's the "guy" who gets me out and that player sometimes is not even the best or fastest bowler in the other team, they just bowl a certain way that messes with me and I get defensive and then I get out