A handful of people share music with me. I've found that I usually like what they recommend. Often, something someone else introduced to me will grow on me so much that I end up using it for my pick of the week. I've noticed that Stephanie has a big representation in the pick of the week lineup. Maybe it's because she informs me about a ton of music. Maybe she has good taste. Maybe it just happens that way.
One of my rules for the pick of the week is that I cannot repeat an artist, ever. This should not be an impossible task since there are enough good artists to fill picks of the week for longer than my lifetime and there are new ones popping up every day. However, when I pick a song recently introduced to me, I don't have to go back and check if I've already used that artist. Sometimes the one song per artist rule keeps me from adding a song I'd really like to (like Days of the Phoenix by AFI), but I think that it helps keep the picks from getting too repetitive and incestuous.