The beat must come from within.
Predicting when the next hit will fall is akin to predicting the future.
You'll need to turn your body into a pendulum:
1. Turn on your beat box / rhythm machine / metronome and set it to a nice comfortable speed.
2. Experiment with different parts of your body to find where the rhythm naturally lives inside you. That part of the body is different for eveyone. Some feel it in the feet, some in the thighs, I personally feel it in my shoulders. One friend of mine says he feels it grinding in his teeth.
3. Once you have found the part of your body where the beat resides, make sure to put that part of the body "into gear" during every count-in.
If you do not feel the beat on the inside, you will always get lost - no matter how loud your drummer is.