PB PM said:
Using liveview for manual focus is all well and good if you shoot from a tripod, but otherwise it is almost useless.
If you read the conditions the OP gives, focus and recompose it not an option.
Well, theirs really no other options. And the only reason focus and recompose is not an option is because he says its not an option, who knows if it actually isn't an option. Their could be a host of reasons its not an option. Can't do it, doesn't like doing it, too slow, but frankly, if your gonna manual focus, I don't see how taking time to focus and recompose is going to make or break a shot. Most things that are manual focused these days should have no issue sitting long enough to focus and recompose. That's not to say people can't MF quickly, but, if you have time to manually focus on it, there should be time to focus and recompose.
Live view focusing, Focus and Recompose, or a D300 and up with the 52 focus point systems are your only options, well, not ONLY, but by principal they are your only options.
Even if their is another way, we would need an EXACT scenario of whats happening. We can't diagnose and resolve an issue without knowing EXACTLY what is going on.
When I focus on someones eye, I simply focus and recompose. It doesn't take that long. If you can do it in the half second from when you say, hey look at me I'm gonna take your picture, and when the person looks away, then all I can say is keep practicing!