Eclecticity has David Packard's 11 simple rules and they are very, very good. An excerpt:
Check first impressions. We are especially prone to dislike some people on first sight because of some vague resemblance (of which we are usually unaware) to someone else whom we have had reason to dislike. Follow Abraham Lincoln's famous self-instruction: "I do not like that man; therefore I shall get to know him better."