Jim
I started off with my cleats fairly central, then made minor adjustments from there.
Remember if your using clipless for the first time, I would loosen the tension on the pedal, (you will see the allen bolt) if your pedals are double sided you will need to loosen both. As you get used to them you can always tighten again.
Nothing worse than stopping at the traffic lights and falling off because you cant get your feet out!
Again if you have not used clipless before, you need to twist your foot sideways to get out.