I don't really change all that much when it comes to settings. The main thing is that I prefer to decouple the auto focus from the shutter button and use the AF button at the back for focusing. Took a bit to get used to, but I really like the extra control it gives me. Oh, and I usually leave the camera in Continuous-Hi shooting mode. Not only good for action shooting, but I also find it helps when the shutter speed is slow - the second or third image in a series often has less shake blur than the first one. The downside is that it's quite easy to fire off two or three frames when you mean to shoot just one
Not really giving me any better shots, but it is a setting - and the single feature I love the most on the K-3: The card slots. I normally save raw files to slot 1 and JPEGs to slot 2 for backup. Which means I can change four or five cards in slot 1 for every card I need to change in slot 2. I never transfer the JPEGs to my computer as long as the raw files are OK.