What I do is a hit the outside of the egg with the back of a spoon until it's all spiderweb cracked.
Then at the bottom (the fat end where the air bubble is) pock the tip of the spoon in and slide it under the membrane the it "spoons" the egg underneath he shell. Then you just twist the egg around the spoon and it seperate a the shell. Once you've done a rotation, lever the spoon away to split the membrane and the shell usually just falls away to a clean egg.