Kitty Nipping at Elbow and Feet

For no apparent reason, your Kitty walks up to you nips you. Of course you react with a loud ´OW!´
It is my experience that Kitty is trying to get your attention when she does this, and since you give such an obvious reaction, she will do it again and again.
To stop this, short step that ´nip´ by picking her up and giving her affection when you see her approaching. Everytime you see her, greet her and talk to her. Take every opportunity to convince your cat that she has your attention, either with a vocal greeting or physical affection or playing with a toy.