Bob Doyle talks about how "like attracts like" is too simple a definition to capture the law of attraction.  He says it's about vibration and resonance, not just that "what you focus on expands" as many people sum up as the law of attraction.

He adds it's not a matter of getting happy all the time; that we're meant to experience the full range of emotions.  (Although we want to dwell on the ones that feel good.)  So your can use your negative emotions as a guide to get back to the better feeling state.  Ignoring them isn't going to serve us.

He also says we don't just make wishes and wait for things to happen.  Rather, part of any manifestation is you working with Universe by taking some action.