I just used a 20 free prints deal at Costco to print out some 4x6's of some shots from a recent trip. These were more than just "snapshots", and I had done a fair amount of post processing to get them to look just how I wanted. I picked up the prints this afternoon and most of them don't look like they do on my computer. Are there any tips (color profiles, color mode, etc.) for making prints look better? I realize Costco may not be the best quality... what other places have pretty good print quality?