From Shine (which is from Yahoo!): Eight Tips for Liking Someone Better (or disliking them less...)
1. Seek contact. This is a bit counter-intuitive. If you don't like someone, you probably feel like avoiding that person, but because of the psychological phenomenon known as the mere exposure effect, we tend to like people better the more we see them.
2. Do nice things for that person. “We prefer to see those to whom we do good than those who do good to us,” as La Rochefoucauld observed.
3. Give that person a brief touch. Subliminal touching, i.e., touching a person so unobtrusively that it’s not noticed, increases people’s sense of well-being and positive feelings.
4. Lighten up. Joke about whatever annoys you, and if you can manage it, laugh about it with that person, or poke fun at your own reaction. Nothing neutralizes bad feelings like a good laugh. This can be tough, however.
5. Act friendly. We think we act because of the way we feel, but often we feel because of the way we act. So act the way you want to feel. This is uncannily effective—just try it.
6. Resist criticizing that person. When you voice your complaints, they assume a solidity in your mind that’s hard to eliminate. When your thoughts remain unspoken, they can more easily be changed.
7. Remember happy shared experiences. Recalling good times elevates mood and will help warm your feelings.8. Be grateful. Reflecting on reasons to feel grateful, instead of reasons to be angry or annoyed, will help change your view.