My cat is bad mannered? How can I make her more lovable?

I have a 3 year old cat named Kiki, I call her kikums. She has very bad mood-swings. I can be hugging her, petting her, and everything nice, then she'll randomly start scratching me! She gets mad walks away then comes back into my room to be petted more after like 2 minutes! I hate her mood-swings and I wish she was nicer. Please tell me how I can get her this way.