How to get my feet out of SPD pedals?
Make sure the release tension is low at first (should be a little screw on face of pedal).  Generally you will get to a point of looseness where you are popping out unintentionally, go just tigher than that.
Cleat placement also can be a factor.  The closer to the toe it is, the easier it tends to be to get out.  Be careful about moving too far from the balls of your feet, it could end up with achy toes!
Lastly, see if the sole of your shoe is interferring with the pedal.  If it is dragging, you can get little spacers that go between sole and cleat.
Don't worry about damaging the cleat, you will do more walking around on concrete.  Also, you will probably fall at least once while getting used to them.  It is almost a rite of passage.