"Listen to your heart" (intuition) told to me by co-worker during a conversation—probably a discussion about discretion. It was my first year. The message I learned is listen to your intuition when dealing with individuals. You can't look at everything in black or white. Sometimes your intuition gives you the answer whether someone gets a break or you need to carry out your duties. As another veteran officer told a guy I just gave a break to: "Christmas came early."
Anonymous
"Never present yourself as being smarter or more knowledgeable than the suspect. You might be, but conducting an interview or interrogation with that attitude gives [them] an unwanted advantage. Be the guy who knows nothing, and you'll confirm everything."
Ken Yarbrough
The best advice I was told as a rookie was: Write great detailed reports, go to every training you can, and don’t forget you live in a glass house. Was true in 1983 and is still true today. Something I always pass on to youngsters.